6max -NL2. CO open limps who is a fish with stats of 37/9. BTN who is a reg raises to 4BB, SB who is a reg folds and we're at the BB. How much to defend here? Should it be more or less vs the case where BTN open raises in BTN with no fish open limping behind
and we're at BB with SB(reg) having folded.

I personally defend more here than when BTN just open raises because there is the fish who most likely is going to call and thus I want to get in this pot in order to play with him.