Bending yours knees, spreading your arms out to form a wingspan, doing the wave with your arms really fast, running up to the closest person, hyperventilating in their face (on purpose, with your nose), making extremely retarded expressions (such as closing your eyes, scrunching your face up, basicly any expression you can think of). When you are epicing someone you usually grab them and are either on top of them or circling them, to show authority.
In all seriousness, I hope you understand what I just said.
Usually, the person being epiced will laugh and say "stop". The effect is much like tickling.
Person #1: SNNNFNFNFNFNNFNNFNFNNFNFNFFFFFFFFFFF
PERSON #2: Oh shit.
Person #1: SNNNSNFSNNSNSNSNSNSNNS
Person #2: Hahahaha stop.
Person #1: *circling around them doing the wingspan wave thing*
Person #2: God damn. Stop epicing me.