Sure looks like it to me. 
https://twitter.com/politico/status/247736744714317825/photo/1/large
Secret Service says he was looking for bad guys. So why is he looking down at his shoes? 
What do you think he was doing?
It does seem to be the classic pose for taking a piss.
Maybe he’s Facebooking on his phone.
I actually don’t think he’s peeing, but it does look like the stance. Who pisses uphill, anyway?
I agree. He wouldn’t be peeing in front of that large seated crowd.
It’s just a really funny photobomb while Obama is speaking.
The problem is it’s just a snapshot. Maybe he was on perimeter duty and and was just looking down or stretching his neck after his mandated visual sweeps of the area.
It is a funny picture though if you’re not trying to use it to score political points. (this line directed at the media)
If I were taking a leak in that location, I would be pointed about 45-60 degrees more to the left than the guy in the blue shirt is facing. One, because the pee would just run down the hill right onto my shoes, and B. because I would actually have my back to the crowd, not give them a one-eighth profile.
The dude between the President and the building is also looking down. What’s up with that huh?
Most people you see out these days are staring down. They generally are not peeing.
Why is he not in a suit?
Where does he think he is, Columbia?
That was my impression too, that he’s checking his messages.
Do you really think the Secret Service hasn’t figured how to handle it when an agent really needs to pee? You don’t think they say something in those walkie talkies and some floating agent comes and relieves them? I mean another agent comes and lets the floating agent get some relief?
He’s on his phone. Look at his elbows, they are just a little too high for him to be holding his dick. They are just at the right angle to look down at a phone held at waist height, however.
Well, if he’s just relieving himself then he’d have done better to go behind some of those bushes in the background, rather than just standing out there.
And if another agent is relieving him, then they’d best both be doing it behind some bushes! 
Gotta be careful where you cock your Glock.
Is he really a Secret Service agent? He’s not in a suit; his shirt isn’t even tucked in.
I think an agent would have more sense than to take a leak right there so close to the President.