when, after giving a blow job, one spits the semen back into the guy's face
Kayla: "Guess what Kelly did last night?"
Kayla: "She totally gave Ben a venetian fountain."
Ashley: "That shit is nasty! I hope he closed his eyes in time."
A Venetian Fountain happens when 3 guys have to go number 1 and 1 guy has to go number 2, but there's only one toilet.
This is how it works:
Two of the guys go number 1 in the upper deck (or reservoir) of the toilet, while one guy sits down to go number 2, and the last guy goes number 1 by peeing in between the legs of the guy going number 2.
If done correctly, a Venetian Fountain can be quite beautiful and spectacular.