What we do now?
Duppa bounce
Dem der duppa bounce
What we do now?
Duppa bounce
Dem der duppa bounce

from M.I.A. – Boyz Lyrics on Rap Genius

Meaning

The duppa bounce is a combination of the word duppa meaning a sizeable blunt and bounce.
A bounce is a type of dance movement eg summer bounce, winter bounce, uzi bounce etc. In other words this is the part of the song she really wants people dancing. The beat switches up for this part too as if to suggest this also. See for yourself:
http://www.youtube.com/watch?v=HnWNSt-MOVw

This could also be another Jamaican dance inspired by smoking weed and involving bouncing. Maya spent six months in Jamaica and collaborating with high profile American producers in preperation for Kala.

To help improve the meaning of these lyrics, visit “Boyz” by M.I.A. Lyrics and leave a comment on the lyrics box