Some all too recurrent themes here..
'Took ages to get hard'
'Could only produce one or two drops of cum'
and then: "I tend to treat cum as toxic waste"
If a guy is very busy as a bottom, then I'd forgive the first two issues and agree in general on the third.
If a guy is straight or a straight top, and looks pretty fit, then I'll usually take a chance on his cum - not least because I do get a buzz out of sucking a guy to completion, and hate having a condom in my mouth. I've never scored any 'issues' as a result.
I don't actively seek out the largest cocks around - I set a lot more store by a really good hard-on than by a large dick - it's quite nice to be able to suck a guy balls deep without gagging. I also like foreskins that fully retract without being helped, and a well defined rock hard knob to play with.
And if guy is going to cum in my mouth, a series of powerful hot spurts is so much nicer than a small dribble..
The guys who work the bars age in their faces much faster than in the rest of their bodies, and whilst those who look cute get loads of attention, it also means they are more likely to be physically spent. Another reason to come back to my favourite idea of glorified glory holes - where a customer can enjoy a slim fit guy's lunchbox and content of his well loaded balls, without being reminded that he is over 30 years old..