R-10 Bakudan Kanojo.

If she and I get more than 10 meters apart, the world will explode. Terrorist group Serpiente has an ingenious method to take over the world: catch dirty old men with honeytrap bomb-girlfriend Cbeta (<-heroine). Her lips are the switch that activates the bomb. But the one who activated them is a regular college guy: me (protagonist)! "You just had to go and snatch that first kiss, eh!?" I learned from the terrorist boss that if Sveta and I ever separate more than 10 meters the bomb will go off and the world will be blown to smithereens---. "There is a way out. You have to come in. Join Serpiente." "Yessir. It makes me sicker than a flipping stomach full of rotten cabbage, but I'll do your bidding." That's how I ended up tethered to my bomb-girlfriend Cbeta, a minion of the terrorists, while they exploited her as a honeytrap soldier, with me linked by her side for who knows how long! Can I save the world in the end? What's to become of Cbeta and me? R-10 Bomb Girlfriend. or... How I Learned to Stop Worrying and F*ck the Bomb.