In my humble opinion there is just one answer. You need to have your friend recommend a ballet class for you. Ballet is very complicated and it's essential to have a teacher who experienced in teaching. Whenever one of my guy friends asks me about showing them the basics, I'll go to a basic class with them, but would not try to teach them myself.
As far as not stretching enough and worrying about muscle strength, DON'T! The basic classes are usually slow, designed to help you build up flexibility and strength.
Almost every ballet school really wants a male in classes, so you would be welcome. Take the time, go to a ballet class!
balletboy[/i]