I know there's been some talk about if vaginas can actually create any kind of suction, and I found a video that inadvertently demonstrates vaginal suction.
The video is titled Raven Riley Getting a Little Dirty, at around the 11 minute 18 second mark, right when the guy pulls out to cum, you can hear a distinct unmistakable sound, almost like an exaggerated kiss, that is the sound of suction being released off his dick when he pulls out. That's something I've never seen in porn before. And I've seen a lot of porn.
If you guys can check it out, definitely do so. The video is available at her website.