I take no credit at all for this glitch but unfortunately don't know the founder.

Requires a Voidwalker Warlock with any grenade.

1. Make sure your grenade and melee charge are both available.
2. Click LB then RB stupidly quick (pretty much at the same time) and the timing can be tricky.
3. Profit, you should have thrown a grenade without losing the grenade charge.

All grenades work but Axion grenades don't stack after one has been thrown and seeking.