..the correct way of hiding the meem in the rule of Iqlaab is to close lips, hold the meem for the length of the ghunna and seperate when reading the baa...

Question
Salaams

I pray you are well. As mentioned, the correct way of hiding the meem in the rule of Iqlaab is to close lips, hold the meem for the length of the ghunna and seperate when reading the baa. When teaching children is it Ok to tell them to close lips so they touch lightly, without pressure, to ensure they are hiding the meem and don't make the meem apparant.

JazakAllahukhair
Wa assalaam

Answer
Wa alaikum assalaam wa rahmatullahi wa barakatuh,
It is better to teach them to hold the with the ghunnah and then pronounce the when separate and not instruct them to touch lightly.  The is pronounced like any other , with collision of the two lips, but with a proolonged ghunnah and then  the separation of the two lips after words is not with a , but with the . 
The way they would make the mistake of having an  apparent  would be if they had no lengthened ghunnah and then released the articulation point before pronouncing the .