One of my players has a build that grants advantages when he is hit, especially when hit by an Opportunity Attack. The problem is that his AC is very high, so straight rolls miss.
My natural inclination is that the AC numbers shouldn't matter. If a player wants to be hit, he could move into the incoming attack. So, as long as the monster doesn't roll a 1, all Opportunity Attacks should land if the Players wants them to. ("Look at me! I'm very slowly running away! I hope all these big bad monsters don't strike me as I turn my back and trim my fingernails!")
Yes, I know that plate armor, for instance, will deflect any blow if hit in the center of the plate, but there has to be some way to expose/open oneself to damage.
I'm having trouble finding rules for when a players wants to be hit. What's the mechanic?