What does Australian base system mean?

Australian base system meaning in Urban Dictionary

The American base system requires: very first base - kissing and breast fondling; second base - handbook stimulation of genitalia; 3rd base - dental stimulation of genitalia; and home base (or fourth base) - the act of penetrative intercourse.The Australian base system is somewhat various: first base - vaginal sex; 2nd base - anal intercourse; 3rd base - threesome with two males and something feminine; residence base (or fourth base) - threesome with two females and something male.