[stevezr1]

Wife's sister, not GF's sister.
She lived with us in our apartment for a while when in she was in college. My SIL was cute, average teen hardbody.
It was not unusual for the SIL to hang out in just panties and T-shirt, no bra of course. Even my wife wouldn't run around the house like that. It really made me crazy when she did that, especially when the wife was not home.

Best part is, our only bathroom had 2 entrances, one from my master BR, the other from the DR. The doorknob to the MBR had an oversize hole and was always loose. So, the whole knob thing was usually slid to one side or the other, offering a complete view of the bathroom, especially the tub.

When the wife was out, I watched the SIL shower and bathe countless times. In retrospect, I'm sure she was totally aware I was peeping on her. She just HAD to know. And, I'm 99% sure she quietly masterbated in the tub with me watching.

Ah, those were the days!