My little Angel

Little Guy is in potty training mode. Yep, it means most of the day spent like God brought him to the world.
My Botticcelli  angel is in no way lessening the load, he still wears diapers at night and at naps, still 3 prefolds a day.
The problem is that he refuses to use underpants. And, if he is wearing a diaper, he doesn't bother to go to the potty, but if he's not wearing anything, then he goes to the potty, takes the cup to the bathroom and dumps the stuff in the toilet, and cleans it!
So I'm confronted with the dilemma of allowing him to be free or starting to push the usage of regular underwear, which I don't know the outcome (is he gonna use them properly or  pretend they are a diaper?)
In the meantime, he's surely enjoying his newly found freedom and doing his part on keeping it that way. It's been 7 days.