Well many many years ago I 'did' the gloryholes...
One thing for the 'big' men, check the hole size carefully....Was at one, gad....25? years ago....the guy sucking was GREAT....and got me very hard...then realized I had swolen to the point I was 'stuck' (someone walked in and I coudn't 'pull free') fortunately teh hot mouth on the other side sucked out a great load (finally) and I was able to 'disengage'.... | 
