Mami was bitten by the original Charlotte, Mami bit Madoka in a fit of playfulness while having tea, Madoka bit Homura (though Homura secretly enjoyed it) when Homura was dragging Madoka away from Kuubey, Homura bit Kyouko when Kyouko teased Homura about her creepy obsession with Madoka, and finally Kyouko bit Sayaka while they were engaged in foreplay.
