Which sign language? In BSL it's an L on its side made up of the thumb and finger next to it of the dominant hand with the rest of the hand closed, and that hand on on the other hand, which is open and flat. Once it is on the other hand's palm you oscilate it from side-to-side gently.
Edit: Ah, we looked it up and it's close to the ASL one, it's still an L on its side but in this case the finger is on the tip of the chin and the thumb is off the face, so it's similar but not exactly like she is doing, nor the emoji.
Edit 2: Accurate signing is important to us, so apologies if we ruined the joke but it's important to communicate correctly in sign else sign language users might be confused.
Edit 3: Okay, so closest we have found so far is French and Croatian Sign Languages π