Usually 30 minutes after the complete ingestion of a McDonald's meal one is faced with McCramps. These cramps are just like regular stomach pains, but differ in the fact that they are brought on by eating McDonalds.
Usually 10-15 minutes after the McCramps/McPains occur one will get the McFarts. These are generally farts with an odor similar to that of death. They reak and reak and generally cause people with you during that time to leave.
Finally, the McCramps get so bad that you run to the washroom and begin to expell feces. These feces are refered to as McShits. They are usually consist of diharea or some liquid and some solid parts. They also have an odor of death, and can cause one to pass out if they McShit too long. Generally, after a good round of McShits, the Large Intestine feels as if it has had an enema, and is generally happy until it one eats McDonald's again.
After the McShits subside you are done with the cycle, or your body may still be undergoing the the "McShit" process, and one will continue to McFart until the McCramps go away. That is the signal to enter society once again.
Matt: Omg Dude McDonald's is so good!
Sasa: I know, but it'll be bad later man, trust me...
Matt: How do you figure?
Sasa: The McShits bro, you'll see.
----- 30 Mins Later -----
Matt: Oh dude this is killing me! Ahh, what is this sensation?
Sasa: Thats the McCramps man... I told you!