No specific trigger- higher strength (1+) needs no reference to a second face of the twin, otherwise talk about the face chin if it doesn't do it on its own, or try

with Ch1nc3pt10n clone face chin

with Ch1nc3pt10n unique face chin

second face on chin, with a unique chin clone, chin clone, unique chin, etc. can work too.

Strength .6-1.5 depending what you want. Start at .8. Gets a little wrinkly at higher strength. using one of the options that includes Ch1nc3pt10n above with other LoRAs helps decrease the effect eroding the other LoRA's likeness in my testing. Not by design, but it works.

Seems to be able to do lots of other insane stuff. Talk about holding a head for example. Or with Ch1nc3pt10n clone heads for ears

Inspired by this Hulk Hogan meme, and I then spent a bunch of time training something based on it and de-Hogan'ing it over several iterations.