Most things have been suggested already. Soft Drinks – half freeze them first so they will be nicely chilled for later on as they thaw out. Reasonable bottle of wine – and don’t forget the corkscrew ! Nibbles /snacks are a good idea – but something you don’t have to pick out of your teeth all night! Box of chocs is good
Spare pack of sealed condoms with receipt. Massage Oil and Lube – remembering that anything oil based is not good for condoms…..
I would also take extra towels as you may both frequent the shower more than the standard issue can cope with! A bin liner is always useful (!) put all the condom wrappers, rubbish etc., in there rather than the hotel bin, if you want to be really discrete. Oh, and kitchen roll is also quite a useful for removing excess lube, wrapping used condoms in etc., Some people have been known to take a bedsheet with them so that they don’t stain the hotel ones….
And don’t forget the 2 brown paper bags, we all know what they are for !