What it means is that he will have to call you back because chances are, he's going to want those drawz and socks back. Consider yourself lucky, you're guaranteed a call back.
It might also mean that you're dealing with a guy who doesn't mind going commando. Which, depending on which brand of vodka you love, could be a good thing or a bad thing. Or it means he's forgetful, and would forget his head if it wasn't screwed on.
What you're wondering is if it means he's trying to establish some sort of ownership, planting his flag, if you will. And no. It doesn't. While men and women definitely like to piss on eachother's legs to establish ownership, leaving boxers behind doesn't really do it. Sock neither. In fact, leaving socks behind doesn't mean a single solitary thing. Think about it, how many people have lost socks in the dryer. He'll probably think he just lost his socks at Starbucks.
Now the question here is what do you intend to do with those items. I mean, you just started seeing this guy, you should probably toss those drawz. I'll put it this way, unless he has a drawer in which to put those items, he probably just forgot them on the way out. If he does it ALL the time, well he's just nasty.
Basically, there's nothing to read into it.
It was written.
I'd just throw them out unless you want to see him again
What if its reversed? as in, what if I constantly leave things at a guy's house that i'm dating and its been 5 months not the first night. The items vary. Sometimes he just leaves it til i come back n get it or he puts it in a bag and brings it to me. Wthat does he think about me doing that?