Does masturbating lower your testosterone levels? i do it at least twice a week?

No, masturbation does not lower testosterone levels. There are no bad side effects of masturbation, as long as it is done in moderation. Enjoy.

It does not depend on the act or its frequency

As you get older your testosterone levels decrease, which is normal. Masturbation doesn't decrease levels, but abdominal fat does, and exercise raises testosterone levels.