The sounds of intense, beautiful laughter ring throughout the ocean's vast expanse as the mermaidized version of Equestria's lovely solar sovereign has unwittingly swum into the territory of an exceptionally large cephalopod that has her tail and raised arms in a tight grip. While in said tight grip, the queen of the seas' belly, belly button, arm pits, neck, and exposed, ample breasts are subjected to the tapered, wiggling ends of the octopus' remaining tentacles. Being as ticklish as she is beautiful (on her breasts most of all), it's only natural that the sensations brought on by all this causes the aforementioned intense, beautiful sounding laughter to erupt from Celestia's (or Sealestia's) throat along with futilely begging and pleading for the octopus to stop and let her go. Of course, that won't be happening for a while.

Original Meme: https://www.deviantart.com/mastuhoscg8845iscool/art/Octopus-tickle-template-906266437

Celestia in general (C) Hasbro, DHX Media, and Lauren Faust