I think he should give you an edging session and see how long you hold out, nipple clamps, vibrator and butt plug, gag in your mouth. If you cum before you are allowed, you have to be given clit stimulation until you use a safe word. ;)
Youngest I go for would be about 20, but would have to be someone with self confidence.
Oldest would be about 55-60, depends on how horny they get as its all about the enthusiasm for me.
Love to cum over a good pair of tits, especially being wanked off onto them by the lady in question.
Having said that letting a woman get a cumload wherever she likes because she wants it is extremely hot!