解剖课变成了与我痴迷的小继妹的秘密搭讪！- 姐姐爱我

Okay, step bro, I can tell you've been wanting to fuck me for a long time.

Oh my god, we shouldn't be doing this.

Our secret, right?

Man, I really gotta study this or I'm gonna fail this class.

Now, what does the male reproductive system do?