Mr. ED = "Mr. Erectile Dysfunction" = a guy who can't get it up.
Brother & Sister having lunch at college:
BROTHER: So, sis, I see you went out with Dick Senormous last night. I have gym with that dude, and his pecker head hangs down below the bottom of his towel. So, did you get any action?
SISTER: He tried, but, he's Mr. ED bro'; his pecker head hung DOWN to his knees all night long. I think he needs a penis reduction. I don't think there's enough blood in his body to get that thing up!
Someone who is hung like horse
Damn that guy is a Mr. Ed, all the chicks want want that 10 inch piece he carries in his pants.