inward v
A reversed v gesture. With the inward V, the back of the hand making the sign faces outward at the viewer or recipient (the opposite of the standard V, which instead has the palm facing out).
The British use this gesture as their equivalent to the middle finger gesture used by Americans. If the character also puts their tongue between these fingers, it can be a cunnilingus gesture as well.
This tag implicates v (learn more).