Bow down before the porcelain god is a slang reference to vomiting, generally following excessive alcohol consumption. The 'porcelain god' is a euphemism for a toilet, while the reference to bowing reflects kneeling in front of the toilet while vomiting, somewhat in the manner of a worshipper kneeling before an altar. Variants include kneel before the porcelain altar.

Similar references include Talking to the porcelain telephone or Talking to Ralph (or Huey) on the big white phone - 'Ralph'/'Huey' being approximations of the sounds made.

See also Toilet humor.