Simple:

1. Intermittent fasting; no breakfast, no lunch, only one massive 100% carnivore red meat dinner a night (aim for at least 4-5 pounds of beef, ground beef, meat, red meat, lamb, beef etc). Ideally organ meats.
2. Very very heavy weight lifting.
3. Walk around topless as much as possible, and booty shorts short shorts. Or if not possible wear a tanktop, and a sleeveless down vest.