Student or Learner
There seem to be divided opinions as to whether you should tip your roommaids in your hotels. There are such words as "pillow money" and "pillow tip" used in some Japanese travel guide books which tell us to leave something like $1 to $2 under or on the pillow as a tip for the roommaid.
Do you use or hear those words in the UK or US whether or not you tip your roommaids?
Leaving it under the pillow seems like a good way for it to get thrown into the laundry and perhaps never seen again. The term "pillow money" seems creepily intimate.
I just leave a few bills on the dresser, out in the open, where it can't be missed.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
I've never heard the term "pillow money/tip", either. And chances are if you did leave money under the pillow (in the US), the housekeeper wouldn't know for sure it was for her and would leave it there lest she be accused of stealing. As Barb said, tips for hotel housekeepers/maids are usually left on the dresser or desk - or in the envelope some hotels "subtly" provide that have "I'm Mary and it's my pleasure to service your room" across the front.
Isn't leaving money on the pillow a cliche for paying a prostitute?