As planned, that press of the finger inside of him shatters his thought process once again, Phillip making a noise somewhere between a whimper and a moan. It doesn't hurt thanks to how much oil is being used, but it is tight and certainly pulls his focus away from literally anything else, especially once Gustavain starts moving it.

His hands making grasping motions at the ground, wanting to hold onto something but finding nothing suitable. Were they facing each other, it's very easy to imagine him tangling them up in Gus's hair, holding on for dear life. But he's currently being denied even that, and the lack of anything to hold onto makes them, and him by extension, more restless and searching. (In his current state, it's probably not hard to imagine just how much 'worse' it would be if he actually couldn't move them.)