This word can be used as a way to express excitement, agreement, horror, or as an adjective (both positive and negative), an adverb, and even a noun (as a replacement for a swearword.)
"Hey-- guess what! I just got my Linkin Park CD signed by Linkin Park themselves!"
"EEP!!!!"
"That is SO stupid."
"Eep."
"How do you know what the monster looks like?"
"Because it's standing right behind you!"
"Eep..."
Kathryn: *sneaks up behind Coral, grabs her ribs*
Coral: Eeeeep!
Kathryn: Haha!
Coral: No fair, you scared me
Kathryn: Yeah, you eeped that said it all *cackles*