When a man or woman straddles their partner and has a bowel movement on their chest or stomach. This is referred to as the steamboat because it was said to have originally happened in an outdoor winter setting, which caused the fecal matter to give off steam once released.
Billy and Cindy wanted to take their relationship to the next level. Boy was Cindy surprised when Billy gave her a steamboat while sitting next to her parents hot tub.
by HDC October 8, 2004

Luke: Hey, get that toilet paper roll out of the garbage for me.
Suzzy: What for .. ?
Luke: Trust me ~ you'll love this. I'm gonna give u a steamboat.
Suzzy: What for .. ?
Luke: Trust me ~ you'll love this. I'm gonna give u a steamboat.
by MoonCricket August 23, 2005

Timothy: "Why is grass green?"
Clarence: "I don't know."
Timothy: "Why do girls have clitorises?"
Clarence: "Steamboat."
Timothy: "OH!"
Clarence: "I don't know."
Timothy: "Why do girls have clitorises?"
Clarence: "Steamboat."
Timothy: "OH!"
by Adolf Skywalker April 20, 2010

Being unbelieveably drunk
OMG I jus drank that whole bottle of wine myself - I've never been this steamboated!!!! CHOOOOO CHOOOOOO!!!!!
by N =) January 22, 2009

having sex with a girl doggy-style in the pool, in deep enough water that she has to keep paddling to stay afloat.
"I was in the pool with Catherine, and we ended up steamboating! The huffing and puffing when she ran out of breath only made it better!"
by Sinker23 May 28, 2006

The term for when you've consumed that much alcohol you think you can actually see Bob Marley in a hula skirt singing 'Baby it's cold outside'. The highest state of intoxication.
Jo: I went to a house party last night and necked a bottle of tequila. I was steamboated.
Bob: Good Times.
Jo: Yeah, til I thought my boyfriend was getting off with the wall and i battered it, and broke four fingers.
Bob: Bad times.
Bob: Good Times.
Jo: Yeah, til I thought my boyfriend was getting off with the wall and i battered it, and broke four fingers.
Bob: Bad times.
by GlewbyDoo_x April 29, 2009

by hostage May 13, 2005
