The Vagina is a muscle so just flex and release over and over again. At the very least every other day for 5 to 10 minute's. Longer and more if you want.
Dont ever retract it. The problem with that however it that you may run the risk if geting infections as a result of not cleaning under it. especialy at first when it is still loose. You don't,...
fat will never turn into muscle. If you want muscle, you need to lift heavy weights and eat plenty of protein. but you need some fat from your food for energy :>