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.

[From DLSite English]