How do you become an Orangutan master? Also b5 master

If you are white you can play b4, but what if you are black? You could try b5, but what if white plays e4?

Do you play a6 and go with the St. George Defense so you can push b5 next? Another option is the Caro Kann and then b5. If you go Pirc, you could try Bd7 and then b5. I also looked at the Sicilian but white can play c4 crimping the b5 style.

What do you recommend?

Well, I can suggest the Black Orangutan gambit :

Well, Stockfish dislikes this one too, but I played it recently.

I've tried both 1. e4 b5?!, and 1. c4 b5!?, I consider them both playable, especially below 2000, where shutting off the opponents theory and getting a tricky position is much more important than an objective advantage

1. c4 b5 Ah, yeah, I played this Jaenisch gambit too.

It's called suck it up buttercup!  You cannot play the b-pawn 2 squares as a catch-all system.

Against e4, there are 4 equally good moves.  Study all 4 and see which is your cup of tea:

1...e5

1...c5

1...e6

1...c6

1...c5 and 1...e6 tend to be more aggressive than 1...e5 or 1...c6, which are better suited for you more defensive minded, more positional players.

I personally play 1...e6, but would never argue that any of the other three are any better or worse.  The other 16 legal moves by Black are all worse by varying degrees.

Philosophical digressions by ThrillerFan. Cool off-topic!

Jeffery Xiong beat MVL with a6-b5.

I would not recommend playing b5 vs the king's pawn opening, hell even the polish defense is a bit questionable 

1.b4 is completely fine, i have played it agaisnt  all level of opponent from novices to a few GM's and not once where any of my loses due to the opening. 

trying to force b5 thematically agaisnt all of white's possible replies is not wise though. for something like 1.g3 you just shoudnt bother.  as for the rest

1.d4 b5, is iffy. if you play it like an orangutan a move down, you  just dont have as many choices. (for example, in 1.b4 bxb2 lines, early c4 is considered best, although some lines with c3 are highly unexplored but playable). as black you will have to settle for e6 nf6-be7 and play by reacting to white's formation. You can also transpose to the st george if you opt for 2.a6 (esp since white doesnt need to take on b5)

1.e4 a6 aiming for a st. george is better than its reputation and black's position at least remains interestingly competitive and complex but i dont think its a reliable defense. Can be a decent surprise weapon though, esp given how underestimated it is. 

1.nf3 b5 is not too bad if white doesnt transpose to polish defense lines, 1.nf3 nf6 2.g3 b5 is a pretty good line though.

1.d4 c6 2.c4 b5!? actually has an interesting trap. 3.cxb5 cxb5 4.e4 bb7 5.bxb5 bxe4 6.nf3? bxb1! 7.rxb1 qa5+ and the bishop falls. aside from this im not fully clear, if black benefits or not from ending up in a st george formation with the c pawns traded off

If you really like the queen flank, play 1.b4 and 1.b3 as white and play 1.b6 agaisnt everything (but 1.g3 and 1.g4) for black, and the 2.b5 lines vs early g3 nf3 lines. The rest are too suspect to be part of a main repertoire for most.

I wouldn't use online bullet games as a theoretical source