Spongebob - I felt the same way about Pixie when I first got her, not because she was always licking, but because she demanded my constant, hands-on attention, which was exhausting!
I work from home, and when she was out, she used to want to be on me all the time (unclipped, so flew over whenever I put her down).
I need to be able to work - not spend all my time playing with my pet. Ultimately I decided that out of cage time would be a privilege, not a right, even though I'd initially wanted a mostly cage-free bird. Pixie is happy in her massive double cage (which takes up half my room) right next to me, has lots of toys, etc and can see/talk to me whenever she wants to. Infact, I spend a lot of time watching her and chatting, so she's gets attention all day. I take her out to do trick-training, flying, scritches, and general hanging out.
Pixie was so clingy at first that I was worried, but I put it down to her being so young (five-ish months now) and so new to us and the house. She's suddenly gotten a lot better - her "not on human but playing nicely on the stand" time has gradually increased.
So anyway, I don't think you can stop your macaw from licking you or doing other preening behaviours. But I think it's necessary for us humans to have a break from our demanding birds sometimes - kind of like moms needs breaks from their kids sometimes. I also don't want to make in-cage time seem like punishment; I've focused on making Pixie's cage a lovely home; but as a new bird-owner, the cage has given me time to work.