someone who gives a lots of sugar during sex
Ali is such a sugar cube! I love her in bed!
This is a small cube. Often made of sugar, ironically. One or more of these cubes is put in tea or coffee by people who have a strange geometric preference to them instead of granulated sugar.
Jardine: "Hey Maurine do you want sugar in your tea?"
Maurine: "Only a sugar cube! None of this powdered crap!"