Can I voluntarily register as a sex offender?

Location: Massachusetts/USA

I am not asking whether or not it's a good idea, I am asking if I can do it. When I google it, it seems like a grey area, where obviously if I commit a sex crime I have to, but if I am "just" a non-offending p*do then nothing. Honestly, I would rather register so everyone knew than to run the risk of actually harming someone.