Here's the thing. If you have to ask, you are already missing the best of the bunch because those guys tend to obey non verbal cues and the men who appreciate them know how to seduce them. And big cock isn't enough. If you want a dedicated cocksucker who does the best job and stays, you need to show that you both desire and respect him for what he admittedly is giving you that you want and cannot give yourself.
But, asking is good, because you can learn to be the kind of top that both deserves and keeps a top notch cocksucker. Unless you are on a fetish site where that is the kind of profile you are putting up, don't ask for it, don't advertise it because you will get an endless stream of wannabes who think your cock is a dildo not attached to you in the same way some man taught them they were only a mouth. Your best shots of that metallic monster, not in the first gallery but there. Change em up slowly and when you get a guy over, THEN explain what you are into (worship and service)...teach em if they don't know. Be patient. One in every 20 will wow you. Call them back but wait one or two weeks. Make the approach to your dick the second time something that is teasing and enticing them. Don't let him have it right away, make him work a little, but make it fun, so you both get aroused. See how slutty you can get him with verbal and non verbal cues. Blindfolds sometimes are good ideas.
In a year or less if you are lucky either your ship comes in and one answers an ad just for that and you are able to charm him or you find a regular who comes back often. Hint, with this guy, find out if he services any other dudes, and be open to listening to him complain or compare...use that information to hook him in more and surprise him...little changes make a big impact sometimes and feeling special is also a good way to feel slutty. Good luck.