Okay, so we are switching DMs to give myself a break from it, and I'm rolling up a level 8 bard to support the current group.

I'm going with whip mastery and improved/Greater Trip and everything else involved, plus the usual bard stuff.

So, I'm not worried about doing damage, I want to help control the battlefield and buff my allies, So, provoking AoO for my allies from Greater Trip attempts seems like a good idea, maybe it's not, but I'm gonna try it.

My question is this, if I carry a main hand weapon (rapier, shortspear, etc; not completely decided yet) and just *hold* a whip in my offhand, I understand that I won't incur TWF penalties because I'm not actually attacking with my off hand weapon, right?

If that is true, then a follow up question/scenario is this: If I *only* use the whip during AoO, will this incur TWF penalties on either my main hand attacks or the off hand?

I have a player that suggests that since I am not attacking with the whip, the whip doesn't actually threaten any spaces, therefore I cannot take advantage of AoOs with the whip. (I think I'm clear on the threat range and attack range of whips, with my feat selections I'll have a 10ft radius of threat [including adjacent squares], with a 15ft reach for attacks.)