Kiddushin 23 - Can a Canaanite Slave-woman be Acquired through Anal Intercourse?
A Canaanite slave may be acquired by means of money, a document, or a proprietary act of serving his new master, such as removing his master's shoe or lifting him.
Can we derive from here that a Canaanite slave-woman can be acquired by sexual intercourse, because she is lifting her master? - No, this is not comparable to regular lifting where the lifter does not get any pleasure. How about anal intercourse where she is not getting pleasure? Who is to say that she is not getting any pleasure? - Disproved! A slave-woman can not be acquired in this way.