you apply the bulge to the genesis figure itself, the clothing should then follow the shape:
select the genesis figure
on the parameters tab filter for ‘bulge’
there are 2 morphs you can use to adjust the bulge
Is that with basic Genesis basic male or M5? I think M5 came with some bulge morphs but not sure if basic male came with some bulge morphs. There may be some free bulge morphs but I do not know where they are.