Teen split both nuts in party game (4,3,6)
I believe the answer is:
spin the bottle
'party game' is the definition.
(I've seen this before)
'teen split both nuts' is the wordplay.
'nuts' indicates anagramming the letters (nuts can mean crazy).
'teen'+'split'+'both'='teensplitboth'
'teensplitboth' anagrammed gives 'SPIN-THE-BOTTLE'.
'in' acts as a link.
(Other definitions for spin the bottle that I've seen before include "party game" , "daring game" , "drinking game" .)