You can try power yoga.

It will increase your flexibility, and it will help you build up your muscles because you do a lot of exercises that involve lifting your own body weight, such as push-ups.

Yoga is one way. High reps with low weights is a way to gain muscle with out bulking up. Flexibility, just do stretches, it is just as important as cardio and strength exercises.

you will have to bulk up, or else you will look skinny with muscle.