Definition: A fun social gathering, as of invited guests at a private home, for conversation, refreshments, entertainment, etc.
This sign with the handshape "P" is also common since the 1980s.
Meaning: Partying hard.
Pronunciation: P-handshape, moved generally twice, with "CH" mouth morpheme.
First 100 words.
As you feel more comfortable with the first few hundreds of ASL signs, progress further with your vocabulary and learn signing more.