Semen and sperm are two different things and Mackey tried interchanging them and was corrected.
As I look through the transcript for the underwear testimony (there was semen found, but not sperm, in underwear---semen that is not Bryant's), I found the part that totally refutes those who still say there was anal sex.
http://www.thesmokinggun.com/archive/kobetranf2.html Q. She never claims anything other than vaginal sex, correct?
A. That's correct.