My first is in pleasure, but never in sleeping;
My next is in smiles, but never in weeping.
My third can be found in both lemons and limes;
My fourth is in moments, but never in time.
My fifth is in children, but not in their cries;
My sixth is in girls, but is never in guys.
My last is in peaches, and also in pears.
My whole, when you find it, is lighter than air!
What am I?