It doesn't really help, the way she clenches around him, but he can't really fault her for it. Eventually, though, he gets a little more used to it, at least comfortable enough to shift his hips again, moving closer to her as he pushes the rest of the way into her.

His arm rounds her torso properly, clinging to her and propping her weight up just so. The movements have his cock shifting inside her and he moans breathlessly, his body shivering slightly as he manages some semblance of a thrust when he moves around like that.