When you spontaneously start to climax for no reason in you're anus.
Spontaneous anal orgasm.
Basically when you cum, anally for no reason at random.
Guy 1:
Uhh yeah I'll have a Big Mac with a Coke..
Oh jeeeeeyzuz Christ I think I'm gonna bust what's going on! Ughgggghhhhhh bro what's happening ?
Guy 2: jeeeeazuz Christ bro. I think you are Sao'ing mkay ?
Sao'ing is the act of spontaneous anal orgasming. Ejaculating at random from the anus.
Sao-Sauce happens when you Sao.
Sao-Sauce is not to be confused with soy sauce, however both are salty and delicious.
Guy 1: Oh dang! I just got Sao-Sauce all over my Spider-Man pj's.
Guy 2: Amateur, you should keep a buttplug in at all times. Or a manpon.