Baseball players enjoy a unique relationship with each other and, within that world, the camaraderie among relief pitchers is ... special. Take the extraordinary rapport between left-hander Sean Doolittle and right-hander Edward Mujica of the Oakland Athletics. In the fourth inning Thursday night, with Doolittle watching, enjoying Scott Kazmir and the A's handle the Seattle Mariners 4-0, Mujica reached out and touched someone -- Doolittle -- just to ensure that he was wearing his athletic supporter. Safety first!

Larry Brown Sports -- they frequently do heaven's work -- was first to widely report the cup check, which was completely ignored by the A's broadcasters. Color man Eric Chavez really missed an opportunity to get into serious baseball #analysis.

The expression on Billy Butler's face was particularly great. He's like, "Yeah, that's how we do it in the big leagues!"

The episode wasn't ignored by others, however. Take, for example, Doolittle's girlfriend:

Jesse Hahn and Sean DoolittleHands where we can see 'em, Mujica (left). Keep sharp, Jesse Chavez. (Getty Images)

She even gave Mujica a new nickname:

Mujica had reason to be concerned, however. With Doolittle rehabbing a shoulder injury since spring training, he hasn't pitched yet this season, and might have gotten away from the best of habits, such as always remembering to wear his cup. Hey, it was for his own good. And, even though the O.co Coliseum dugouts are uniquely placed, Doolittle was still in harm's way as he engaged Marcus Semien in conversation after Semien had tossed a foul ball from the field into the dugout.

Hahn Doolittle
Jesse Hahn (left) and Doolittle hangin' out, unaware of who lurks in the shadows.(Getty Images)

The lesson: Pay attention at all times (watch your back), or else a teammate will grab your junk. For your own good.