Honestly I'd been toying with the idea with my boyfriend for a while since she's super adventurous, but unfortunately it's uncomfortable to him to be uh... soaked for so long ahem. I've heard stores though of guys falling asleep in their girlfriends, having an erotic dream or sensation and growing hard inside of her and having additional relations with her while she slept until she woke up. Some women commented on finding the feeling of a man's erection growing in them to be much more pleasurable than penetration and men said the sensation of a woman flexing and squeezing on him with her peristaltic muscles was out of this world.
Actually, he sometimes likes to leave it in afterward, and we have gone to sleep like that. It's nice, but there's no way it can stay in very long. You both move around and roll over, it softens and slips out.
I am a female and have tried this with my boyfriend. We always wanted to do it. However, he was not able to be inside of me without continuing to have sex. It was hard for him to fall asleep while he was in me. Very hard for him. But, we tried. Maybe I'll try again when he comes back from work one day and he isn't so energized before bedtime.
it sounds like it would lead to a really uncomfortable moment when the guy is limp and the girl is dry. The sentiment is cute, but its probably really uncomfortable.
Plus, its very hard to maintain an erection at all without some degree of constant stimulation. not moving inside of someone is not sufficient stimulation. you'll go soft long before you go to sleep unless you are *incredibly* tired or are using tranquilizers to induce sleep. A soft penis gets pushed out of a vagina pretty easily, if the actual loss of erection itself doenst "shrink" it out.
all in all sounds like something that only works in your mind or movies like the standing 69, making love 6 times in one day or the pull-out method. (yes those three are meant to be jokes)