If they are blessed with a dick then why to avoid using it? Or they just can't do that because it doesn't work anymore?
If you think as female - it's OK. Girls use strapon to fuck another girl or a guy. And females still remain females. It's OK to change roles sometimes. Lets be open-minded in sex.
P.s. 2 shemales: if you let your bf to suck your cock and don't let yourself to fuck him then you're teasing him cause a lot of guys would like to be fucked...at least one time in their lives.