My girlfriend and I share an old house in the city with another couple. They have the top two floors, we have the bottom two. There are no keys for the doorlocks in the house, but we trust each other.
It so happens that our bedroom faces their bathroom. There's a short flight of stairs in between, but if I open my bedroom door, I can look right into their bathroom. Of coursen usually when they're in there, they close the door.
I don't remember what triggered me, probably the fact that I was home alone and horny. I was working at my desk in a room adjacent to our bedroom when I heard my upstairs neighbor talk on the phone as she walked into her bathroom. It was a hot summer day and she was talking about meeting the person on the other end of the line as soon as she had showered. And then something triggered me. I silently walked to the bedroom, kneeled down before the door and peeped through the keyhole. Sure enough, there was my neighbor walking around in the bathroom, taking on the phone, wearing only a bikini set. She's a pretty girl - the petite kind, with small tits and a cute little ass. I got a hard on almost immediately. And then it happened. She got off the phone, casually took her top and undies off and only then closed the bathroom door. I got up and stood there with a huge erection as I heard her open the shower. I only spotted her for the briefest of moment, but it was fantastic. It's always fantastic when you see someone you know naked, isn't it?
Weeks passed and I had a new hobby. Every time I heard her walk to the bathroom and I had the opportunity, I'd sneak a peek down the keyhole. Sometimes I'd see, sometimes not. Sometimes I was too late, other times I was right in the time for the bingo. I'd see her scratch her pussy before she got in the shower or rub her tits a little after she took off her bra. More often than not, she'd only close the door at the last moment.
Then came today. Sunday. My girlfriend is out for a weekend with her friends and this morning, I heard the guy who lives upstairs leave too. So I patiently waited in bed until I heard her come down for her morning shower. Sure enough, around 10 am she came down. In what had become almost a routine, I peered through the keyhole, saw her enter the bathroom naked, turn on the shower and... keep the door open. This was new, but I liked it. I sat on the bed until I head the water stop - from my viewpoint I couldn't actually see her shower - and peeped again. There she was, in all her wet glory, casually coming out of the shower. She stood there for a moment, glancing in my direction, even though I knew she couldn't see me through the hole. I'd checked when they weren't home: no way you could see something through the keyhole from the bathroom floor. I was thinking about this when - suddenly and swiftly - she tiptoed down the stairs and stopped right in front of my door. I felt a rush of adrenaline, the kind you felt when you were little and your mum caught you masturbating. "Mercutio", she said, with a firmness in her voice. "I know you're standing there. I can see your shadows under the door."
Fuck, why didn't I think of that? I was beat. "I'm... I'm sorry", I mumbled. "I couldn't help myself."
She sighed. A million scenario's went through my mind. She'll call her boyfriend. No, the cops! No, she'll tell my girlfriend! She didn't. Instead, my neighbor - still naked, still damp from the shower - knocked. "Can I come in?"