The Lips
There are two articulation points for four letters.
The first point of articulation is for the ف, the other one is for the ب-م-و.
The bottom edge of the front two upper incisors touches the inner bottom lip.
ف
Circling of the two lips without meeting completely. This Waaw is not the Waaw Madd. و
و
Closing the two lips together.
When pronouncing the م, part of the sound comes from the mouth whilst the other part comes from the nose.
ب