New here, I think this fits in this thread most appropriately. My GF and I lived with another friend in an apartment in grad school. The roommate had a BF but he was out of town and for some reason she adored me and was very friendly with me. It was all platonic, and then her and her BF started having problems (not my doing at all) - basically they had intimacy issues. Since she felt so comfortable talking to me and all, she asked me how me and my GF dealt with these things. Like the nature of such talks these didn't remain confined to that, and turned into full blown sex talk about what she liked and what I liked etc. She was a very physical person when it came to showing her affection, and I liked this largely cos it felt nice, it was warm. In the scope of things, i think it would be appropriate to describe her; she was tall thin and had smallish breasts with a generally athletic straighter body. She did have a cue tiny ass on her and long legs.
Over many months our talks became more and more intimate and less about her BF and her who by that time had almost decided to call it off, and unofficially things had pretty much ended. Our talks also brought to my knowledge her bisexual tendencies and how she liked my GF and would like to get it on with her. I was excited and we would talk for hours on end about how to make this happen when my GF was out. During most of these times I had a raging hard on, and I always went commando. Ever since things had started to become less platonic between us I had started wearing these loose cotton shorts around the house and before each of these talks adjust things (by placing a webcam where her eyes would be to check what she saw

) so that she would see my tool. I basically wanted to flash her. A lot of times, I think she may have seen it but she never admitted to it, although that is an impossibility unless she was completely blind.
We had become quite close, and in course of conversations she would mention that she didn't like her boobs and wished they were bigger. I always told her that I think they looked nice (based on the cleavage and DBs i had seen, I didn't even lie) She always attribute it to wearing push up bras. I asked her to not wear a bra once so i could appreciate it, but she remained shy about it. She did dress with lower wider necks around the house so I could get a very limited, but definite view. I always made it a point to tell her that I looked and she told me that it embarrassed her, but on the other hand it felt good. I started trying to convince her, that she probably worries too much and that I found her hot. She kept saying that I don't know cos I have never seen them blah blah blah. So I told her that may be she should show me. She was raised in a culture where women do not show cleavages or partial boobs or thighs etc., (no she wasn't a Muslim or whatever) so this was scandalous to her.
I remembered her mentioning in one of her relationship talks that she didn't like her BFs penis, because it wasn't big enough and he didn't shave his nuts or pubes. So i asked her how big it was and she showed me using fingers. So I told her that that isn't too bad, he looks bigger than me (he didn't) but I said it anyways. From this point I played the "insecure about his penis" to her "insecure about her boobs". I sent her pictures of models with small boobies and asked her to compare them to hers and most times she was appalled and felt kind of bad for them and commented that hers were bigger. I told her that most of these models were already a good size (good aesthetically and play wise, not huge, most were A cups).
I continued to suggest that she should let me see to let me decide for myself and she continued to remain bashful. We often talked late into the night when my GF was sleeping (she knew of course). We would talk about this at length in the depths of the night. She always had this smile on her face which indicated that she found this quasi flirting/seduction enjoyable. She would complain about her boobs, I would complain about my dick. I would reassure her and she would say I don't know coz I haven't seen them, and she would reassure me and I would say the same thing.
So one night as these same talks were transpiring, we reached an ultimatum. It was either her boobs being inspected by me which made her bashful or my penis being inspected by her which also made her bashful. Months of flirting, banter and talk led to a pretty pleasant and unexpected surprise - she chose penis inspection. This pretty much led to o an instant hard on. So we were sitting with our legs stretched out at opposite ends of the same couch, so we were kind of intertwined. I asked her how she wanted me to do it, and she chose to close her eyes. She was super embarrassed and red by this time and almost giggling like a school girl at the nature of the event about to transpire. I just had my shorts on, and i put my thumbs in the waistband and announced that I am doing it, and she was about to say something and opened her eyes a little and asked me to wait, but by this time my raging hard on in all its glory was out pointing skywards due to the super hard erection that I had because of her. She looked away almost amused and this is when the good part started
I was a little perturbed because this was first time for me flashing my aroused genitals to a girl who I wasn't sleeping with. But soon the thrill and excitement emboldened me and I began to enjoy this which basically fueled my hard on. The best part of all this was that even though she was looking the other way, her eyes kept turning back. I had by this time adjusted my shorts well below my balls so she could see well. Since I wasn't wearing a shirt, i was pretty much naked there. Her first reaction was that she thought I was huge and massive and that I was stupid to think that I was as big as her BF (In modesty, I am just about average may be a little over, I am very similar to the BD guy in squirrel's post, and it was probably her BF who was smaller) This was only the second adult penis she had ever seen in her life. Her embarrassment was obvious and entertaining- her body and brain were betraying her and she basically could not keep her eyes off and yet her sensibilities told her that she should not be staring at her friend or her friend's BF's erect penis.
Eventually she caved in, and did get a full frontal look, and the look on her face still gives me a hard on when i think about it. Now bear in mind this is a girl who didn't consider herself sexual and here she was smacking her lips gently and licking her lips and close to salivating. Her eyes never left my penis (which flattered me) and she was like a teenage boy with raging hormones talking to a buxom lady unable to take his eyes of the boobs. All the while she kept commenting on how "beautiful" it looked and how clean and "delicious" it looked. I told her she could touch it if she wanted to, and I suspect in that state she didn't trust herself to maintain control so she declined. I asked her to point out on mine how big her BFs was and gingerly brought a finger to a little over half way mark making sure not to touch it. I am uncut, and I pulled back the foreskin for her now, leaving the head shining. And this seemed to fascinate her even more.
By now she had moved closer and was about like a foot from the apparatus i had on display. I was stroking it gently, and she was acting like she was pretty much mesmerized. Her hands and fingers were never in contact but didn't go too far either. I have very prominent veins on the underside, and those did it for her. She eventually started tracing them all along my shaft. It was here that I erred, and suggested that may be she should go ahead and just grab it, which kind of jolted her out of the trance like tracing and she jerked her hand away. Finally she suggested that I tuck it back in, before somebody (my GF, or another friend of us who was staying with us that night) wakes up. I do have to thank her BF who was small and didn't shave his pubes or balls for creating the effect it did for her and making me look so much better.
This was actually the first of the few incidents which happened before we moved to different apartments, but this is going to be with me forever.