Lucky I never had such encouters. I have seen people push the
heads of sleeping strangers, and the sleeper still never wake up
wor! .Anyways if no one is looking, maybe purposely step the foot
of the sleeper, think he/ she will wake up in shock. hahaa.or sort
of softly slap their face from the other side. e.g. left cheek on
your shoulder, u softly touch their right side.