There’s two of them stationary with their bums in the air looking like they are licking the hive?
Signalling with their nasanov glands.
It contains a pheromone which the bees use to attract returning forager bees.
You see it quite a lot when new bees are on orienting flights and when you hive a swarm and the bees are indicating where queen and home is.
The licking the hive part sounds like they’re washboarding.
The bees were pretty stationary, so i don’t think it was washboarding. Though i’ll keep an eye out for that. It’s all new to me.