Any one I see far behind who looks like they are busting a gut to catch up with me, I slightly raise my cadence, nothing too strenuous on my part but enough to make them work a little harder but still allowing them to get nearer to me. Then as they approach my rear wheel I slow giving he impression I've cracked, heeheeeeeee, and let them pass, heeheeheee then as they do so I jump on their rear wheel and get a nice tow for however long they are going my way. They of course will continue to bust a gut to maintain their futile over taking move as they won't want to lose face and in doing so they will do all the work pulling me along. Ha-ha! If obviously they do slow right down as they are just weak cyclists then I just burn straight past them leaving them with egg and ignomy on their face. I'm gone. Heeheeheeeheeeeheeee. If you have a persistent wheel sucker then just fart a nice long low frequency tunnel shaker. This should get rid of them.