While definitely nowhere near as much as it is in hentai, there was one time I was jacking it and released way more than I normally do (and ever want to again).

I hold a tissue over my dick when I'm about to finish so I can catch it all without spilling, but for some reason, this just outright overflowed and was starting to get on my hand. It was flowing down and was about to drip onto the floor, so I instinctively moved the tissue in my other hand to wipe it off, which was a mistake because there was a glob of semen that the tissue couldn't absorb and dropped on the floor. While this was happening, little did I know, my little D wasn't done spitting yet, and it was running along my shaft and onto my boxers. After wiping most of it, I had to go back to the bathroom and wash the rest that got stuck in my pubes off.

Cleaning up was hell that night; I wasted so much more tissue and alcohol than I needed to.

In case anyone wants to know what I was jerking it to that night:

Crazy Taxi and Battlefield V

And yes, I fap to two games simultaneously (by having the Dreamcast connected to a TV and my gaming laptop on my lap) so I can maximize the amount of games I play and fap to, and also because the time it takes me to nut is a lot longer than how long it takes me to play through a typical 20-30 minute BF match (or more specifically, the 10 minute time it takes to complete a leisurely tour of the city in Crazy Taxi while dying in BFV). Normally it's a good thing if you don't nut that quick, but since I don't have a girlfriend/wife I need to please, I'd actually rather be able to finish in under a minute so I can sleep earlier.

Weird thing is I wasn't even backed up. I make it a point to wank everyday before I sleep so I don't have wet dreams and cream my shorts the next morning. The only times I miss out is when I'm on a trip with family, and don't have a room to myself, but those are usually just 2-3 day trips.