to kowtow; to show unnecessary respect or deference in order to win favor with a superior or colleague. Annoying, ingratiating behaviour that is observed by others. Usually used with pronouns, he, she, you, rather than with actual names, John, Sylvia. The origin is probably derived from the idea that great pleasure is derived by the recipient of fellatio. Hence, giving someone one more pleasure than they deserve in hopes that they will be so pleased they will feel obliged to give you benefits, usually in the form of job security, more hours at work, more favorable shifts or to have her/his opinions favored and adopted.
I don't suck cock. He sucks cock at work.
A colleague may question, "How come he gets to work all the good shifts?" whereupon someone might reply, "Oh, he sucks cock."