As Judy said by 2 they know that when I tell them to do something they better jolly well do it and right away, lol. I do not negotiate. Sleeping on a mat is a privilege earned by growing up and kids love to be like the big kids so that helps. IF they don't do it correctly as in continually get up they lose the privilege and go back into the playpen which is put up in the playroom too with a stern warning given as they are tucked into their mat. When they play hard all morning they are exhausted and welcome naptime as much as I do. All my kids are under 3 and arrive by 7:15 in the morning so by 1:00 they are ready.

Also kids that fooled around and didn't stay on their mat which if anyone is usually the older kids then I make them stay there a few minutes longer while I get the others up and they absolutely hate being last - well being first is a privilege earned.

You also need to adjust your naptime according to need. Just because you want them to sleep for 2 hours doesn't mean that the particular group you have does.