Extracted from "The Biography of Emperor Wu of the Hun Dynasty," as quoted by Laurence Bergreen in "Marco Polo: From Venice to Xanadu" (page 219).
Step	Woman's sign	Man to	Woman's desire/response
1	Her face grows red	Slowly press near	If her thoughts desire the union, her breathing will become irregular
2	Her nipples become hard; her nose moist	Slowly insert penis	If her vagina desires the union, her nostrils will distend and her mouth will open
3	Her throat becomes dry; she sucks back her saliva	Begin to thrust slowly	If her vital essence wants to be stirred, she will move her body up and down
4	Her vagina becomes moist	Sink penis deeper	If she wants to fulfill her desire, the liquid emitted from her vagina will soak her clothes
5	Her vaginal emissions drop between her buttocks	Move freely	If she is about to reach orgasm, she will stretch her body and close her eyes