I would not read into what you see in movies—the long line of kisses down the chest/stomach is more for film than standard practice. Some men like it, others are probably just impatiently waiting for the main act, and may feel more desired if you convey urgency rather than teasing. If talking about “it” explicitly makes you nervous, you can get on your knees in front of him while he’s seated on the couch or something and look up at him and ask, “is there anything I can do for you?” A good way to make your intentions clear in a sexy way while getting consent without having to talk about it. Depending on how frequently you have these urges, you can tell him after you finish him, “I want you to tell me when you need me to take care of that for you.”