Well then...

Please register your new weapon by performing "coupling".

Huh?

C-...coupling?

By making contact with your lips to form an oath.

Or a kiss, in other words.

It's the rule.

We won't allow this unless you do that, get it?

It is a sign of respect for the weapon you use to fight, to which you entrust your life. In addition...

by physically matching the devices in your collar with your weapon...

...it becomes possible for you to carry a weapon 10% denser than your body for interplanetary travel as well.

If you do not couple with a weapon of large mass, it will vanish when you teleport between planets.