optimist12,
If you are flaring and the inflammation is at the end it can be difficult holding it in. You might want to ask for a script for Cortifoam. Its like a mouse and it disolves in the colon, very easy to retain during the day and evening.
As for the enema make sure its warm not cold, run under water if too cold.
Squeeze the air at the top out.
Insert and squeeze some medicine in, maybe for the first few days only insert half the bottle in the evening.
Stay still for a few minutes until the urge goes and then move to your bed and lay on your left side for the night.
I have had to take an antispasmatic to calm the colon down during certain flares in order to help retain the enema better.