It makes sense for Wailord to have Spit Up and Stockpile, but not Swallow, like Qwilfish. Wailord exceeds at inhaling air (check its Pokedex entries). Inhaling air is why Qwilfish and Drifblim get Spit Up and Stockpile. Air also explains why Qwilfish doesn't have Swallow (fish don't swallow air, and a balloon kinda does).Sabreholo, here's no precedent for a mon getting Spit Up but not Stockpile or Swallow. If you want to use Spit Up then those are the other two moves in your quota.