I have been trying to achieve this effect for a long time with existing models, now I finally managed to train my first video Lora.

It requires a fairly specific image in order for teh effect to be realistic, an image of a womans vagina with good detail from a lower angle, and the slit needs to be somewhat dilated.

I trained it on LTX 2.3 Base model, and it does not understand the vaginal anatomy well, so I recommend using another lora for that purpouse (Dr3aml4y or Sexgod nudity).

Version 2:

Trained a second run with a few more clips and on 10Eros which helps the anatomy a lot.

Same triggerword but can now use a bit more temporal control in the prompt like:

pre orgasm phase, orgasm buildup phase, orgasm peak phase

Some control over the degree of moaning:

subtle moaning, slight moaning, intensified moaning, intense moaning, hyperventiaating

I also tried to achieve different types of motion effects with:

vagina pulsations, vagina contractions

It seems to have some effect, but vagina pulsations being the dominant motion

I also experimented with:

wet vagina, glistening vagina, creamy vagina, cream bubbles

..with varying results.

T2V works, but anatomy is a bit off, need some more variety to the dataset.