While we're in the middle of this lovely emotional roller coaster, I'd like to take this opportunity to enjoy a short intermission and share a tiny grammar lesson.
None of these things have apostrophes (well, except for "s'mores," because the apostrophe indicates that something is being skipped over, turning "some more" into "s'more").
When you say "bottoms up," you mean "put the bottoms of your glasses up in the air, and get drunk and/or hydrated very quickly." The bottoms of your glasses are just plural, and thus do not need an apostrophe.
When you say "heads up," you mean "put your heads up, because you're about to get smacked with a baseball." Your audience's heads are just plural, and thus do not need an apostrophe, either.
When you say "cats and dogs," if you're just talking about several cats and several dogs, you do not need an apostrophe, and if English is your first language then these were probably the first two words you learned how to pluralize in first grade so good lord please tell me you know better.
Hey, speaking of podcasts, you can listen to the podcast R. Stevens and I put on every week, called Coffee and Cider! We just chat for half an hour about... everything. Mostly being work-obsessed idiots and human beings who like beverages and have cats.