Sailors use this term in a derogatory sense with reference to others who are extremely useless. The fid is a device used by sailors to untie stubborn knots. This is the only application for this equipment, hence the derogatory connotation.
Ace: Wow champ really blew the big game last night, he ran the wrong way with 20 seconds left.
Gary: Yeah, that champ is a real fid.
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.