I mean... she must make sure he is in good health, what better way to check his temperature?
The tongue is probably her most heat sensitive part of her body.
And his penis is where his blood flows very near skin level with core body temperature.
So... yeah... totally makes sense.
Except now he will be still in the cold with an erection... she better protect him from all that cold.
I suggest sheating his penis somewhere warm and also embrace him.
I mean... it's just the responsible thing to do.
Totally.