We really need a secret handshake, don't we!
I don't know, balancing the potential self-consciousness against the joy of finding 'another'... I would certainly prefer to be spotted by a sympathiser.
As long as it is done sensitively away from the group, where there is definitely no risk of humiliation.
Personally, I don't underdress, so if I get spotted, I am bang to rights.
Are you certain it was a bra?
How would you feel if the positions were reversed?
