underoos

We bought new Star Wars undies for my four year old and he found out a kid at his school has the same ones.  The other morning my son was going through all the scenarios of his schoolmate having one pair on and he having another pair.  He would wear Boba Fett one day and then the kid would have Boba's on the next day.  They were out of sync.  Then he says, or tries to say, "It would be my pleasure to wear the same one with him."
Except he didn't know the usual string of words "it would be my"  but he sing-songed something like it all garbled up with pleasure in there.