My dog won't put his... you know what... away?

I know this is a weird question, but this is the first dog I've ever had in my life, so I'm unfamiliar with the ways dogs act....

My dog (black lab/blue tick hound mix) has been very excited to be around me today. So much so, that his wee-wee is making a permanent appearance. Not just a little peek... I'm talking about a full appearance.

Like I said, this is my first dog and I've only had him a couple of months. He's still under a year old. But he's also fixed. So what's up with him showing his... um... urges?

What's also weird is that he seems to only be doing it around me. When he's with my husband, he's not as "excited".

Is there something wrong? Or is this natural? Can someone explain the what and why of his sudden new state of arousal-- if that's what it is? Or could he just be "airing it out"?

Thanks...

T.