The best replacement for mouth is nose breathing.

The best alternatives to mouth are rated as following:
★★★★★  nose breathing
★★★★  human mouth
★★  nose
★★  therabreath
★★  water moccasin
★★  advertising
★★  human\u0027s mouth
★★  dog mouth
★  humans mouth
★  armpit temperature
★  thermacare
★  nose first
★  human's mouth
★  dogs mouth
  oral cavity
  ear thermometer
  nose breathing when running
  chicken pox
  skin
  sidearm
  soda mouth
  thirst
  traditional advertising
  canine mouth
  armpit
  here comes the pain
  in the throat
  water snake
  thrush
  regular mouth

Your alternative for mouth is not listed? Suggest!
Speaking about mouth, one probably shouldn't forget about teeth on roof.

Other search terms related to mouth and their ratings are:
★★★★★ teeth on roof
You have in mind a companion for mouth and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of mouth in all years. Click on graph for more.
mouth
nose breathing
human mouth