Transmigration: Brother is such a Yandere

A transmigrated girl has been transported to an ancient era by a system to be reborn again.

But the problem is.....

system: host the mission is to make love with the male lead

her: what!! why!? and who is the male lead anyway?

system: the male lead is your big brother and you need to extract a total of 340 positions

her: ∑(￣□￣;)