It happened to me many times. While travelling in Bus or Train, the person seated near by me may fall into sleep and slowly put his head on my shoulder.
It is really unacceptable because I don't want to support a stranger's head and I feel very uncomfortable.
But, since he is doing it unknowingly(I mean in his sleep), I don't want to be rude.
At present, I adjust myself to move a little to other side so that this won't happen.
But I would like to know how should I tell him that I don't like this without being rude?