look up any word, like tribbing:
 
2.
Another word for ejaculation, or spunk etc. Is often used in the programme Bo Selecta.
oh my god i think i did a sex piss in my pants!
by joapet August 06, 2004
 
1.
An unexpected, sloppy way in which an individual male will urinate the morning following a night of intercourse. The male ejaculate left to dry in the penis offsets the flow of urine causing a terrible misdirected aim.
John woke up with a hangover, went to take a leak and sex pissed all over the shower curtain.
by Adam A September 15, 2003
 
3.
to violently eject, or ejaculate a long plume of creamy white semen onto oneself when thinking about sex, occasionally (but not always) taking the squirter by surpise
E.G.
JOHNNY BUMSEX: "This fit bird was bending over on the tube, and i had a funny feeling and did a big sexpiss right there in my pants."
by JOHNNY BUMSEX January 23, 2004