Is this the equivalent of leaving stuff at his place? Nah, just my over-active Mr. Gutter Brain trying to lead me down the wrong path again. Dammit. Although, him needing (aka wanting) to give her the sock back may have been a well placed means of guaranteeing they'll meet again. Nah, stalkers don't need such trivial socks ... I mean, tactics.
Edit: Also, a wet stinky sock ... is she playing 3d chess? The innuendo here is WILD.