I thought I'd share the answer to this question I get asked quite often.
First, I would like to point out that we do not pay anyone to wear North South Jiu-Jitsu Underwear under their gi. All of the amazing grapplers that wear them do so because they love them. I get comments like "send me as many pairs as you can. That's all I wear" all the time.
There are 2 ways that those athletes got North South Underwear.
It all started with a friend training at Alliance headquarters with Fabio Gurgel. His training partners saw him wearing our athletic underwear and were intrigued. We sent a few pairs down south to guys like Michael Langhi, Tarsis Humphreys and Renato Cardoso and they fell in love with them. We were at the testing stage at the time but they already wanted more. The best compliment was (I hope I don't get choked unconscious for revealing this) from Tarsis. Before he got the underwear, he said he preferred rolling commando style but after getting North South he was converted as he felt he was commando. IBJJF Worlds were coming up and Langhi, wanted one of his best friends, Bruno Malfacine, to have some so we sent a few to him. Bruno proceeded to win the Worlds and sent me messages saying they were his lucky underwear and would wear them from now on at every competition.
The other way is by simply offering free product to the athletes I looked up to. North South is fortunate enough to not be in direct competition with Gi manufacturers so we are not trying to sway someones allegiance from one brand to another. The other thing is I never asked for anything in return. I send the product and hope for the best. I did that with Seymour Yang (Meerkatsu) and even though he has his own line of apparel he gave North South a rave review. Every single athlete I sent the underwear to is now representing the brand just because they love the product. The only person I couldn't mention that was wearing them was Caio Terra. Now that he has changed sponsors and wears War Tribe gi, he finally got a bunch more underwear and wears them proudly.
The jiu-jitsu community is a great one. I don't know if it's because of beating on each other but the openness and respect that exist is amazing. Every single one of those guys are very very nice guys and we are fortunate to belong to that group of people.