An Erection For Mum

I would like to ask a question, I keep getting erections when I am in the presence of my mother it is not intended it just happens, it first started one morning when I was eating breakfast in the kitchen, my mother has a good body for her age, I got an erection when she was bending over with her bottom right next to me sorting out a cupboard, I kept looking at her bottom I knew I shouldn't have, I went to the bathroom and relieved my self,
I thought the reason for my hard on was I hadn't had a wank for three days and nothing to do with mums bottom nearly in my face. When I leave for work we hug and kiss before I go, it happened again I was bulging so much it could be seen, now it happening very frequently every time I am in her company even talking to her I can not control it, she has noticed it
and keeps glancing at it occasionally she has not said anything. am I the only male who has a hard on for his mum I just can not stop it happening, I know what I want to do. any comments please.