turtle genitalia question

Hi, I’ve had my mississippi maps for more than a year and only in the last month I have noticed something… The turtle which I believed to be a female has been stretching her penis in and out from her anal passage. (I know it’s a penis because the end of it looks like a beautiful black rose and the rest of it is an inch in length when fully out) I’m assuming she is a male now. The reason I thought she was a female was because of her long front claws and her short/fat tail. Anyway, my question is: does it mean anything when the penis is stretched in and out like that? ‘He’ gently scrapes it against the gravel and has the most tiny orgasmic spasm type movements whilst doing this. I can’t seem to find anything on the internet which reflects what this behaviour means. Any help would be appreciated. Thanks. Devi.