1. Ikhfaa - when the letter ba comes after a meem saakinah, make ghunnah for 2 counts and keep the lips slightly apart.
2. Idghaam - this is when the meem saakinah is followed by a meem mutaharrikah, meaning a meem with a fathah, kasrah or dhammah. Make ghunnah for 2 counts.
3. Idhaar with the Lips - the meem is read clearly without any Ikhfaa when it is followed by any of the letters of the alphabet other than meem and ba.
Rule of Meem with Shaddah and Noon with Shaddah
The rule for both is: you must make ghunnah for 2 counts whether stopping on the word or carrying on after it.