You tell John about your micropenis

The next day, you go back over to John's place to hang out. You try to act casual and not too eager as he lets you in. The two of you chat as you watch half an episode of a show before you find yourselves making out again. You grab his ass, enjoying the feeling of his cheeks in your hands as you melt together on the couch. He gently grinds against your leg as he kisses your neck, making you moan. Your hand creeps up the back of his shirt, feeling his skin. You want more, but...

"Uh, before we go any further, there's something you should know," you say nervously, pulling away "I... well, I have a micropenis." John sits, processing for a moment, before smiling.
"So what?" he says, "I mean, I'm trans. I don't have a penis at all. It's no big deal."
"Sure, but..." you blush, "it's really small. Like, I don't know if I could even penetrate you."
"You don't know?" he asks, raising his eyebrows.
"I'm a virgin," you confess, "I've always been so nervous about having this conversation, I've never even tried." You blush, unable to look him in the eyes.
"Fortunately, I'm a trans guy," he says with a smile, "Specifically, I'm a trans guy who has had a lot of sex with other trans guys. Don't worry, I know all sorts of ways to have fun without needing a big dick involved. If you want, we can try out some strap-on sex, and there's always hands and mouths."

You blush, realizing you don't know whether or not you're ready for someone else to see your micropenis. John seems to sense your apprehension.
"Or, if you want," he says, "we can stay fully clothed, and just keep making out for now."
You're attracted to John, but also nervous about having sex. For now, you decide to just continue making out. John resumes his kissing of your neck, which makes you moan and squirm
"Mmm, you like that, don't you?" he asks.
"Yeah," you breathe. He runs his hand up your thigh, getting tantalizingly close to your crotch. He pauses.
"Can I touch you there?" he asks, his mouth by your ear.
"Yes," you gasp, nodding enthusiastically, and his hand presses against your groin. He continues kissing you as his hand explores your crotch, feeling the shape of your balls through your pants, and his palm presses over the rock-hard nubbin that is your micropenis. This is the first time your virgin cock has ever been touched by another person, even over the pants. John grinds against your leg as he kisses you hungrily.

You begin to feel a certain tingle in your groin. You've always cum pretty fast when you masturbate, and you're not that surprised to be already feeling the beginnings of an orgasm building, since this is easily the most erotic thing that's ever happened to you. You're not sure what to do - you don't want to embarrass yourself, but you really don't want this to stop. You try to act cool, to not to let it show how weak John's touch is making you, but your body is betraying you. You can feel your little dick twitching as it oozes precum into your boxers. You've never been more turned on.

Good as John's hand feels on your bulge, you breathe a sigh of relief when he moves his hand away from your crotch and up to your chest. He moves so that he's basically lying on top of you now, his thigh planted between your legs, rubbing against your crotch as he grinds against you. You'd thought that him moving his hand away would allow your cock to calm down a little, but this feels amazing. He tweaks your nipple through the fabric of your shirt. You've never tried playing with your nipples, and this new sensation takes you by surprise. With that, the pleasure is too much. You try to jerk your hips away from his thigh, to control yourself and save yourself from embarrassment, but it's too late. Your balls tighten as you feel yourself pass the point of no return, and your body goes tense.
"You like that?" John asks, clearly not realizing just how much you like it.

You can't reply. All you can manage is a sharp, shuddering sigh. John kisses your neck and continues grinding as you grunt, cum gushing out of your throbbing micropenis and soaking your underwear. Your face is flushed, your breathing rough and ragged. As your orgasm comes to an end, John reaches his back down to your crotch, and confusion followed by surprise is visible on his face as he feels what must be a sizeable wet spot on the front of your pants.
"Did you just cum?" he asks.

Your face burns as you nod, too humiliated to speak. He grins.
"That's hot," he says, kissing you again, "It's been ages since I've made someone cum in their pants. I thought I'd lost my touch." His tone is playful and sweet, but you still feel incredibly embarrassed.
"I should go," you say, getting up.
"You don't have to. If you want, I have a laundry machine here," he offers, "You could wash your stuff and stay the night." Part of you wants to stay here with him, but a larger part wants to go home and hide.

You say a quick goodbye to John, and hurry to your car. The cumload in your pants grows increasingly uncomfortable as you drive home, but you're just glad that there's nobody in the carpark or the hallway of your building to see the wet spot. Once you get home, you strip off and take a long shower.

When you get out of the shower, you look at your phone and see that you have a message from John:
"Hey Sam! Sorry about today, I got carried away while we were making out and forgot that you might be kind of sensitive. Don't worry, it's not like you're the first person ever to cum in their pants while dry humping lol. Anyway, if you wanna do it again sometime (or do more), I'm down."