The act of being upset over a very menial situation such as not being invited somewhere or having information withheld from you unintentionally. One whom becomes butt hurt easily also is great at verbal accusations in lieu of physical altercations.
Josh: Dude... no invite. COOL!
Brandon: Boohoo
Chris: Ya'll get butt hurt too much. Here's some ice for your bruised ego.
Kyle: I need a hooch.
To become offended or upset (such as you would after taking it in the ass in prison) after a smart-assed comment is made. Most of the time it is over something pathetic
This emotion usually stems from an unfounded sensitivity to a superficial prank, joke, or durogatory statement. It's most hilarious uses are on highly religious or homophobic people since it also implicates the hyper-sensitive person as being a big Mo if male, or an anal-receiving Sperm Sponge if female.
I don't know why Tom Cruise got so butt hurt about that in the closet episode on South Park when he probably owns his own astro-glide production plant to keep up with the amount of anal lube he goes through.