Ha. good question. I went to a workshop earlier in the year on something along these lines. We divided into three groups and their was an assumption that the bottoms would act in some role plays. Other members of the group went quiet when this was raised so I spoke up and told the organiser to stop being so silly. I was sure a bunch of tops/switches could role play as a bottom - but probably not so politely. I was quite miffed at the assumptions made that a bottom/sub would respond in such a way to just anyone who calls them self a top.
There was a lot of 'looks' - whatever they are supposed to look like
And nervous twitches - disguised as raised eyebrows
There was hand on back of necks, on throats, invasion of personal space. I forget the rest but I recall these were the main ones suggested by all participants.
Me - looks will make me laugh, twitches - oops I mean raised eyebrows worry about their health, and if someone grabs me in some way I will resist. hmmm but there is a some sub in me, it just does not appear through the usual channels?