This is a very common phrase among middle scool boys and is code for a secret society has told them they must keep about themselves. It roughly translates to "I'm a flaming bisexual."
Dude, did you see (insert male name)'s ass today? Blep blep!
The act of sticking ones tongue out in an adorable manner, usually in response to a prompting comment or an action called a boop. Commonly used in accordance with pet owners or roleplaying situations.
A blep NORMALLY is used for animals sticking their tongues out of their mouth but I've seen a post in reddit of a woman disguised as a turtle with a crown apparently blepping. Man I hate reddit.