A (female) friend of mine once asked me to look after her plants in her apartment while she took a two-month study-abroad trip to Japan. Since her apartment was pretty much right on the way home from class, I agreed to stop by to water them every couple of days.
The first day I stopped by, I went into her bathroom to fill up the watering can (it wouldn't fit under the kitchen sink faucet) and saw that she had a huge free-standing bathtub. Why was this important? Well, my very early (teenage) masturbation experiences had all involved the classic 'lie-in-the-tub-and-let-the-faucet-run-on-your-pussy' method of masturbating, but since I had gone to college and moved into a dorm, I hadn't been able to enjoy my 'traditional' method of masturbating. Instead, I had to settle for a quick clitty-rub under the shower or wait for my roommate to be gone so I could whip out my vibrator and have some quality pussy playing time.
Almost immediately, my pulse quickened. It hadn't taken but a second for me to realize that this was my chance. My friend was not only out of town, but out of the country, so there was basically no chance of her walking in on me, but the idea of using my friend's tub to masturbate had a naughty feel that turned me on even more. I quickly went and made sure the front door was locked, then stripped completely naked and turned on the faucet.
While I waited for the water to get warm, I began to get some guilty second thoughts, so to put those out of my mind I started playing with my nipples and wondering if, just maybe, my friend had also used that perfectly-placed faucet for some private pleasure. The longer I thought about it, the wetter I got, and I could almost picture my friend with her legs spread, water pounding her shaved (?) cunt.
By this time, I was almost trembling with excitement as I stepped into the tub. It only took a minute for me to 'assume the position' and the familiar feel of warm water massaging my already swollen clit made me moan aloud. I positioned myself a little more exactly, so I could control if the water poured on my clit or between my labia and then began slowly humping that hot stream. As much as I wanted to make it last, it only took a couple of minutes before I had an absolutely exquisite orgasm.
Well, needless to say, I made my friend's apartment a mandatory stop on my way home after that. After the first few times, I became more relaxed about it, sometimes bringing my favorite porn with me to read, or even my vibe, which I used on my clit while I kneeled doggie-style in front of the faucet, letting the water tease my asshole and imaging what a rimjob would feel like (!).
As the date for my friend's return got closer, I began to get even more adventuresome, masturbating in other parts of her apartment as well; in her chairs, on her bed. And when I very carefully did a little exploring, I found a small, white vibrator under her bed. It took me all of five seconds before I had slipped my panties off and was lying in her bed, using her vibrator on my pussy. It had a different feel and speed than my own (which I prefer), but the very idea of using another woman's vibrator on my cunt (one that she had used and would use again) made me cum harder than I'd ever come before. I know I should have felt guilty about all this, but by this point I was too carried away with my 'masturbation vacation' to care.
After my friend got back, she thanked me for taking care of her plants and the irony of telling her 'it was my pleasure' was almost too much. Thinking of all the things I did in that apartment became my primary source of masturbation fantasies even to this day, and I hope that some of you will enjoy yourselves as you read this as well. Thanks for listening!