Mexican Leak
When you're anally penetrating a female with your erect penis and, in your dominance and glory, decide to release a small amount of urine into her asshole. After all, why not?
"I was banging that bitch I met in the bar last night and was balls-deep inside her ass when she thought I came. She asked "Was it good for you?", and I replied "Not yet, you dirty whore! That was just a Mexican leak! Now shut up and hop back on my dick."