Hi @Jinzo ,
I LOVE the Melts! In terms of suction toys for PIV, it is far better than any Womanizer I’ve tried because it doesn’t get in the way. Here is a link to my review of the Melt 2, any questions after reading, please feel free to ask.
Having said it’s the best suction toy for PIV, no suction toy is particularly good at staying perfectly in place if the action gets, um, particularly exuberant. If I’m honest, for clit stimulation during PIV, I would pick a wand (ideally the Mantric) over any suction toy. If you don’t have one yet, you need a suction toy for your girlfriend because they’re amazing and, in my opinion, the Melt 2 is the best of them but for clit stimulation that stays in place during sex, get a wand or, maybe, a couple C-shaped toy.
Edited for grammar as running grain carts while typing 