Onna Senshi Liber

The Goblin tribe faces a crisis of species annihilation.
There are only six male goblins left in the world.
Their death is only a matter of time...
That's when the goblin ruler speaks.
"If we bump-donk-gack some human females, we'll have ten children in a day!"
And so the goblins set off on a mission!

[From DLsite]