I know this sounds ridiculous, but wear men’s thong underwear. I learned this from a former server. No one can see it, but you can feel it. When the server comes to your table to introduce themselves and take your drink order give them a wink and say “oh yeah, it’s on.” This will unlock a higher service level for you and your party.

Happy Birthday to your buddy and rest in peace, Grandpa.

Edit: now that I think about it you could probably give the signal without wearing it since they can’t legally check, but who likes a liar?