I was taught in OW not to put my mask on my forehead as it could be interpreted as a sign of distress and doing so incurred a beer fine (I owed a six pack by the end of the course...). On a later course I asked my instructor about it, saying I thought a distressed diver would either leave their mask on or chuck off their mask rather than place it on their forehead and
he agreed saying the whole MOF idea is a conspiracy by instructors to get more beer.
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
And also said really the concern with MOF is that it is easier to lose if a wave knocks it off or something, not that people will think you are distressed. In boats and in shallow calm water (where I can duck dive to retrieve it) I put it on my forehead, and in rough and/or deep water it stays on my face.