Ask Caleb: What Happens to His Cum When He Finishes Inside Me?

A bottomsplainer: the biology (and mess) of what really happens when someone ejaculates inside your ass.

Over the past few months, I’ve gotten a flood of emails, DMs, and late-night questions from guys who are curious about sex between men but don’t always know where to turn for answers. Some are shy, some are bold, and some are just plain horny, but all of them want the truth, not the boring, clinical version. That’s why I’m starting Ask Caleb: a column where I take your questions about gay sex, intimacy, and everything in between, and answer them the way I know best; with honesty, experience, and a wink.

To kick things off, I thought I’d start with a question that lands in my inbox more than you’d think. It came from 19-year-old Devin in Denver, who wrote in with the kind of curiosity most of us had at his age (and let’s be honest, plenty of us still do).

Before we get into it, a quick note: I’m a huge advocate for safe sex. I’m actively on PrEP, I test regularly, and I believe every guy deserves to feel both horny and healthy. So while we’re going to talk about cum and all the messy fun of being filled, know that I always approach these conversations with safety in mind.

“Caleb, when a guy nuts inside me … what actually happens to his cum? Does my body absorb it, or does it just leak out?”

I love this question because it’s one every bottom has thought about, but not everyone says out loud. And honestly? It’s one of my favorite things to explain, because it’s not just science; it’s experience. Let’s follow a load from the second he cums to the moment it inevitably leaks out, with a mix of biology and what it actually feels like in my body.

💦 The Moment of Release

When a guy finishes in me, I feel it instantly. His cock swells, starts throbbing, and my hole clenches down like it’s trying to hold him there forever. There’s this pulse-after-pulse rhythm that tells me exactly what’s happening, every spurt, every rope. It’s hot, it’s heavy, and sometimes I cum myself just from that sensation of being filled.

Ejaculation happens in rhythmic contractions, usually less than a second apart. Each throb pushes out 0.2–0.5 ml of semen, propelled by the prostate and pelvic floor muscles. That’s why the “ropes” feel distinct your body can literally register every contraction.

🍑 The Heavy Fullness

And the feeling right after? Fullness. Not fake fullness, not “oh he’s big and stretching me” fullness. I mean the kind that makes your body ache in the best way, where you can literally feel something sloshing deep inside. I shift my hips and it moves. If he stays inside me, plugging me up, I can keep it there for a while, savoring the weight of it. I’ve clenched on guys just to keep them in place, grinding, moaning, loving that I’m stuffed with more than just cock.

Once ejaculated, semen collects in the rectal vault, a stretchy chamber just above the sphincter. The rectum isn’t built to hold it for long, but for those minutes (or hours, if you stay lying down), the liquid sits there, pressing on nerve endings that make you hyper-aware of the fullness.

🧬 Absorption vs. Release

Now, to the technical part: does my body absorb it? A little bit, yes. The lining of the rectum is semi-permeable, which means some of the proteins, sugars, even hormones in semen can get absorbed into your system. It’s not like it disappears into me completely, but traces of him do become part of me. I like that thought … that my body holds onto him in ways I can’t even see.

But most of it? It doesn’t stay forever. Gravity always wins. If I stay on my back, it pools and eventually slides out slowly, warm and sticky. If I get up too soon, it gushes, running down my thighs, dripping over my cheeks. I’ve ruined sheets, I’ve stained towels, I’ve had to sneak into bathrooms in hookups’ apartments with cum literally slithering out of me, feeling dirty and grinning about it.

Small molecules like prostaglandins or fructose can be absorbed through the rectal wall, which is why a “trace” of him literally becomes part of you. But the majority, especially sperm cells, exit the way they came in. Movement, gravity, and muscle contractions (even walking or coughing) speed up the leak.

🍯 No Two Loads Are the Same

And here’s something you learn when you’ve taken a lot of loads: every guy is different. Some shoot quick bursts, hot little ropes that leak right out as soon as they pull out. Others pump and pump until I can feel it overflowing around their cock before they’ve even finished. One guy filled me so deep that when he pulled out, I pushed and a puddle hit the sheets beneath me. Another stayed inside for twenty minutes, cock soft but plugging me, and when he finally pulled out, his cum oozed so slow it felt like my body was sighing in release.

Semen volume ranges from 1.5 to 5 ml on average, but hydration, diet, hormones, and time since last ejaculation all change how much comes out. Viscosity matters too, watery semen leaks fast, thicker semen clings and oozes. That’s why no two loads feel the same.

🛁 The Lingering Reminder

So yes, some gets absorbed. Most leaks out. But the real truth? What happens to his cum when he finishes inside me is that it becomes a part of the experience, a mark, a memory, a mess. Hours later, when I roll over in bed and feel the wetness between my cheeks, or I catch a streak down my thigh while walking, I’m reminded of what happened. That’s why I crave it. Because his orgasm doesn’t end when he pulls out, it lingers in my body, dripping, soaking, reminding me I was filled.

Semen doesn’t stay indefinitely. Within hours it either leaks out naturally, gets wiped away, or is washed off. But the psychological memory, that mix of sensation, intimacy, and mess, lasts far longer.

💧 The Answer

Biologically? Your body absorbs a little, but most leaks back out. Erotically? It becomes part of you in a way no textbook can capture. His orgasm doesn’t vanish it lingers in your body, marking you, reminding you what just happened.

And that’s the part I never want to lose.

✨ Stay Curious, Stay Slutty

If you liked this column, make sure you don’t miss the next one. Ask Caleb is just getting started, and every week I’ll be answering your real questions about gay sex, intimacy, and everything in between, no filters, no shame, just truth (and plenty of filth).

👉 Subscribe now to get every column delivered straight to your inbox. Free if you’re curious, paid if you’re a real slut for details.

Love,
Caleb