How to teach them not to pee on their pants?

We just finished day 4 of training (basically using Oh Crap method) with my 26mo son. It's going really well overall - resistance definitely kicked in on day 2, and he's freaked out by poop, but accidents have been minimal and only happen when we (the adults) aren't paying close enough attention. We've mostly been naked at home, but starting to wear pants commando, and I struggle to see how to teach him to use the small potty (IKEA) without peeing on his pants/shoes. Any suggestions for how to teach this? Right now I'm just fully taking off his pants every time. Do you just do that? He also prefers the big toilet with a seat reducer sometimes, so maybe we just go more all-in on that? Any advice welcome; I feel like such a newbie FTM!