The effects of being around a ginger is well known. One day they look at you, eyes glowing and extract your soul. What isn't known is the effect of the soul extraction on another ginger.

What if they try it on each other?

It all depends on the soul level of the other ginger. As you know Gingers, lacking souls of there own consume a massive number of souls from living beings such as humans for sustenance and to become more powerful. The number of consumed souls contributes to the Ginger's Soul level.

First of all Gingers cannot extract souls from each other as easily as as they can from real people since Gingers have evolved exclusively to trap collected souls deep within themselves. Because of this the gingers must try to force the souls out of each other by doing battle (That is what their freckles are used for) The losing ginger is vanquished back to their own dimension. Then the winner absorbs a portion of the losers collected souls that make up the losers soul level. The receiving ginger can receive anywhere from 10% to 37.5% of the total souls the other ginger used to level up depending on who is attacking who. the maximum number of souls that has been acquired by one ginger from another was 496771, from a max level (850) ginger. However weak gingers cannot absorb as many souls. they're just not strong enough to take them. For example two 140 level gingers could steal about ten thousand of the other's souls, however a level one could only manage to steal a bit over one thousand.
Also a ginger has been called to defend one ginger from another he wont be able to take any souls.