A peter (n.) is a person who ultimately rejects, or even insults, friends of the hot girl he seeks in conquest. Petering (adv.) is a practice not generally accepted among groups of females and generally leads to the "peter" being denied by the group, and possibly even cock-blocked for the rest of the night.
A better strategy than to "peter" the friends is to compliment them and tell them nice things and immediately be entered into the girl circle.
Petering (v.) can be completed in various ways. Please see below.
For example Girl 1 (friend) "So Peter how are you tonight?" (Peter) "I'm actually just interested in your friend." Another way to peter the group of friends is to insult them about other frivoulous flaws, i.e. ugly elbows, man hands, etc.
In the rare case "petering" can be completed by a female. However the case of the female peterer is rare because we all know exactly how to get what we want without resorting to being a peter.
Peter: "Wow what beautiful elbows you have, and your hands are so femine. Your friend has ugly elbows and manly hands but yours are perfect!"