Conservative political group Crossroads GPS, co-founded by former Bush adviser Karl Rove, is notorious for spending millions on political advertising, most recently doling out $20 million for anti-Obama ads. It wasn't until this week, however, that the placement of their ads drew as much attention as the content.

A tipster notified The Hill that one of the group's "blank check" ads — with the message that President Barack Obama's spending is out of control — have begun scrolling along the bottom of a smartphone app called Grindr. Grindr allows gay and bisexual men to locate other gay men in their immediate vicinity, opening the door to a sexually-charged encounter.

Crossroads spokesman Jonathan Collegio told The Hill that the ad was distributed by a mobile advertising network, so the group probably has no choice about where the ads appear.

“Ads may run on thousands of websites and apps but are based on the user’s history and profile, not the platform on which the ad appears," Collegio said. "So if an ad appeared on that platform, it was triggered by the user’s history and profile meeting the targeted demographic criteria, not the platform itself.”