I thinks it's called Jennifer and Sidney in three parts (I mean "Jennifer & Sidney pt1", etc)

This is EXACTLY what it was. Do you by chance know where to find it?

Hard to figure out from the details given. Sounds potentially like Hypnosisfetish or Entrancement Video (at least, I can think of videos from those two that would fit the description; both sites' material would be harder to find than any that are currently active; and both had curvier models more often than some other inactive sites). Do you remember what the setting was like? It it was in front of a black curtain, it was probably Hypnosisfetish; if it was in something that looked like a hotel room or someone's living room, it may have been Entrancement Video.

I found this set of gifs. It seems to be from promotional material, as it includes some after-the-fact interviews with the subjects. These two segments (being told to shake their breasts and give themselves a wedgie) seems to be from the same show.

These are from the 'Sailesh in Iceland' DVD. It pops up on ebay from time to time. Its is probably one of my favourite bits of hypno content!

The source was indicated at the beginning of the clip. I tracked down the movie from there... title is “Growth” directed by Gabriel Cowan

https://www.imdb.com/title/tt1300159/

Thanks a lot! I did stumble upon 2010's 'Growth' related to this clip (and with other parasite scenes) a few times, but my preliminary combing-throughs did not find the scene, so I figured someone had mixed clips from different parasites. Guess I'll need to go through it again.

That's not the right clip.