Well as far as wiping quickly and cleanly in as little time or as few wipes... we now do 'downward facing dog' a yoga move that allows me access to my 23 month old dd's bottom in full view - without her having to lie on her back. And she gets to do a fun bendover type move. I say 'downward facing dog' and she goes right into the move.
We have been potty training so it is easier because she is used to pull ups and being naked and getting off the potty and going right into the bend over move. I can get everything in one or two wipes.
the move you do is just a regular bend at the waiste but the hands go forward away from the feet so your body is in like a V shape upsidedown. I also have her spread her legs apart. This is the same move employed in the shower for cleaning so she is used to it. It only took a couple of days for her to 'get' this move.
I would be armed with a swipe of lanolin on one of my fingers so I could blob it right on her bottom after the last wipe.
Does your DS let you put medicine on? or bandaids? could you tell him you want to fix his boo boo?