Why do people keep saying tap the head? It's not a puppy..

I'd never do that. Especially if it were something like a Retic that does not forget or forgive actions like that. Reptiles are not mammals and do not learn in the same way.

Use a small hand towel to quickly cover the snakes head completely. Then very quickly scoop up the snake from behind and underneath. Usually they are fine once they are picked up. If it remains in strike position, just keep your hands under it and gently try to run your hands along its body from underneath to in coil it. Handle it so that it is forced to move and crawl along. It quickly figures out that you are no threat.

I agree that it was likely kept in a small tub. It's overwhelmed by the huge environment, new scents, new sights, etc.. It's terrified and probably thinks you are a threat.

I always say to never reach in going towards the front of a snakes face. Never reach in smelling like food either. As far as getting tagged, I'd rather be bitten by a young BP any day than a rat or any other mammal.