From the outside, it looks entirely too sudden, maybe punishing even. Viktor barely gives him time to adjust to each finger before there's another one, and even though the longest pause is for three, it's still not an amount of time that's careful in any way. It leaves Yuuri clawing at the pillows when Viktor pushes in, gasping for air, but if Viktor even so much as tries to slow down on his behalf, Yuuri gets a leg around him and tugs him in faster. If Viktor wants to set a slow pace on his own, Yuuri will absolutely let him, this is about Viktor, after all, but he refuses to be coddled right now.

So whether Viktor needs the warning leg or not, it will fall away after a moment anyway, and then there's just Yuuri shuddering slightly under him, whole posture an invitation. He definitely gives the impression, in that moment, of letting Viktor choose what kind of pace he wants, if he wants to draw this out or take his prize more quickly.