You may grab a hold of one thing that is currently within arms reach of you.
When you are ready you will be transported into a small arena with a random uma
https://umamusu.wiki/Special:RandomInCategory/Main_Characters
Now you much try and survive for 3 whole minutes.
She will become pacified and follow you into the real world as your uma wife if you manage to survive
However should you fail and get captured you will become a women and get impregnated by the new futa uma.
Why yes this is the plot of that one coliseum manga
