Jay dog,
My surgeon cautioned me against straining and said if I do not feel like the pouch is completely evacuated do the following: stand up from commode; bend over forward as far as possible with arm firmly pressed against abdomen; then sit back down on commode. In addition to that step I have also found through trial and error that when I am reseated on commode if I twist and contort my upper torso sharply to my left while holding lower torso in place on commode, it will promote evacuation of remaining contents of the pouch. These are things that like Scott said are trial and error, and you kind of need to experiment with body movements to come up with what works, which is what I did in adding this second step. In your case it might be a twist to the right, but I have found that the left leaning contortion gets the job done. But I would first try the step my surgeon recommended and see if that helps.