I just bought the tummy tuck jeans off the I love jeans website. They are not a miracle cure but boy are they better than those sodding low rise jeans which are in the shops nowadays, which make the old muffin top 10 times worse. These jeans mean I don't have to wear massive jumpers to avoid the unsightly muffin roll. They are pricey, but I think worth it as I may never take them off!
The only exercise I think has worked for me is swimming, which does flatten the tummy a bit. But after two caesareans, I was also starting to look at smartliposuction, till I found the jeans!