"Walking home last night I bumped into these two Finnish sisters looking for a houseparty and ended up shagging them both in some guys spare room!"
"Fucking hell mate, buce!"
Also used as a subtle, quick method of agreement in situations where a longer and more enthusuastic response would be inappropriate or
even dangerous. Such as letting your mate know you
clocked that bird with the big knockers that just walked past when you're with your
girlfriend.
A knowing look might be passed and a quick "buce!"