Take off Trish first

If Jessica was really someone else in a Jessica suit before you zapped her, wearing her might be complicated enough already. You already have the Jess suit on up to your knees and your feet are her beautiful and dainty ones, but you remove the suit entirely. Now it's just a matter of taking off your Trish suit and becoming David again.

You don't want to. The brown "pen" has given you Trish's memories and personality and the David ones lurking beneath seem unreal. You have to. You concentrate on imagining that your Trish skin is opening up so that you can take it off.