Read manga: Blue Drop - Tenshi no Bokura

manga
Summary:

The Arume, a dominating alien race of female humanoids (alien lesbians) has conquered Earth. With total control over the world they have begun live experiments on humans.
One day, out of the blue, a girl that Shouta Yanami has never seen before in his life arrived at his house asking to have sex with him. How will this end for Shouta Yanami?