Chaps Before Baps
See Bros Before Hoes

The unwritten law that the Chaps (friends) should always come before Baps (female with whom you are/hoping to have a relationship with). Most used as a trump card by your Chaps when they feel you are becoming whipped or are blowing you off for the Baps
'get here at 8 we're hittin the town hard tonight'

'..no can do spending time with gf'

'wtf chaps before baps, bros before hoes, we'll see you then.'

'fair play, see you then'