FWH in PM?

I don't have the ability to do AG batches, but I'd still like to try FWH-ing my beers. So, my question is: how does this technique translate over to partial mash? Do I just put in the hops after the steep and while I'm bringing it up to a boil? And then keep the hops in for the whole boil?

I suggest putting the hops in at the time you begin the steep. Thats 20-30 minutes, plus the time it takes to get that up to boiling, which for several quarts , wont be long..
When I make partial mashes, I start the main kettle heating before the PM is complete. so there isn't really much elapsed time between the end of the steep and the boil.

You don't need to FWH. I brew IPAs via PM all the time. Simply use a lesser amount of low cohumulone hops for bittering to get that smooth bitterness. Combine this with a small middle hop addition at 30 along with a lot of late hop additions and you'll have a very smooth IPA, even at +100 calculated IBUs (as long as your gravity is +1.065). If you're really set on FWH, you can add the hops to the mash (mash hop). I would do this in a bag. One bag for the grain, one bag for the hops. This can be done in a smaller kettle. Then when you sparge (or dunk your grain bag in the mashout temp. water to rinse the grains) in the larger kettle, you can swap the hop bag to that kettle and start your recipe as usual.