When the female has reached a certain point in her monthly cycle, the vagina begins to leak blood, skin, hair etc. This can sometimes be 'splashed' on innocent dances or members of the public.
"Ahhh. I just got attacked by that bitch's gash splash"
when a woman needs to urgently piss and doesnt have the time to take her dress off
friend:"wow that was a fast piss!"
pisser:"yeah i had a quick gash splash behind that caravan"