Yes, it seems popular at the moment. It’s… okay. The negative about most toothpaste is that many brands have little particles in them to try and get your teeth polished and that can irritate you and be bad for you if you get it inside your pussy. And obviously it’s not designed for internal use like that.
On the whole the blue gel toothpaste, which doesn’t have the particles in, is a better bet, but it still gets sticky. There is proper balm designed for this, search for Arousal Balm somewhere like Lovehoney. That’s your best bet as it’s actually designed for doing this (but it tends to be pretty weak)
For the serious masochist then you have stronger menthol ointment as described in the post below. For the brave it’s definitely worth a go.