while I find it awkward some people love it.
your tips get billed to your room and if you leave it as is then on the second last night you will get little tickets and envelopes to put the tickets in. each envelope has the persons duty on it ie-head waiter, room host, server, asst. server. you can add money to the envelope if you wish to top up ones tip. that is totally up to you.
then the last nigh you go to dinner, act like its nothing special and eat. when dinner is over you will hand each envelope to the appropriate person. usually the head waiter swings around mid meal as he doesn't see you often and you get to hand it to him them. its a bit of a show for you to pass it to him and he to thank you while slipping it in his pocket like he feels awkward to.
now there is a box at the front door as you go into the dinning rooms where you can also put your envelopes in, but again, if I have nothing to hand the servers, I feel they think i'm stiffing them. that's my phobia

. last cruise I watched the wait team take the prepared drinks from the table next to us as apparently the family were not coming to dinner and the team didn't look happy. I got the just that maybe they did not want to tip.
to me its just all so stressful, but that's just me. I take that feeling on and no one makes me. the servers are very nice.
for some reason giving the room host his envelope is fine. if I don't see him I just leave it on the bed when we go to dinner and its magically gone when we get back.

k, so i'm making a big deal over nothing. can't be helped cause.........its awkward! lol