What is the best way to put on more mass FAST?

There is no fast way to add mass. The faster you gain it, ultimately the faster you'll lose it. It may take 9-12 months to add significant lean mass. The best way to gain lean mass and keep it is to make sure you're following a strict workout program and maintaining a proper meal plan.

Check out the SHF Meal Plan system. It will show you exactly how to eat for your body type and goals!