I don't know why but I've developed a strong desire to see a good looking girl sticking her (long) tongue out. NOT in retarded cross-eyed ahegao, just normally and erotically.

It serves multiple purposes from serving as an invitation for a fellatio or kisses to confirming that a girl swallowed everything and her mouth is clean.
But also even if a girl is just doing solo performance, her sticking out a long sexy tongue is really erotic anyway.
I've even seen a webcam girl that does nothing but showing her sexy tongue and it still makes me cum buckets.