Peg left after party - you and I followed (5)
I believe the answer is:
dowel
'peg' is the definition.
(a dowel is a wooden peg)
'left after party you and i followed' is the wordplay.
'left' becomes 'l' (common abbreviation).
'after' is a charade indicator (letters next to each other).
'party' becomes 'do' (do can informally mean a party).
'you and i' becomes 'we' (we means you and I).
'followed' is a charade indicator (letters next to each other) (some letters go after others).
'do'+'we'='dowe'
'l' after 'dowe' is 'DOWEL'.
(Other definitions for dowel that I've seen before include "Fixing peg" , "Fastening peg for joint" , "Peg used in joinery" , "Peg used for fastening two adjacent parts of a structure" , "Wooden peg" .)