>>25854The psychological component of "marking my territory" most certainly applies, at least in my case.
I get rock hard thinking about my girlfriend's pussy, full of my cum and all used up. This happens within maybe 5 minutes or less after fucking her the first time around. I'll go in for round two and it just feels so primal, dirty, and simply fantastic to fuck her and feel my cum already in her.
She adores it and we're "fluid bonded" and STI tested so I've no worries on that front.
She's something (who am I kidding, she's super into it) of a sub. It's only happened once, but we've gone out to see a movie or dinner and she's been buttplugged with cum in her. Privately degrading and just perfect for her.