I caught sight of myself in the mirror and actually paid attention to what I saw when my first child was about 2yo and knew something had to be done. I started my pregnancy as a relatively healthy 50kgs (110lbs), all trim and svelte with boobs I once considered 'sat too high'. Ha! I gained about 25 kilos (55lbs) through the pregnancy, and then slowly continued gaining afterwards. I worked out hard
for 6 months (3 hours a day for 3 months, 2 hours for 2 months, 1 hour for one month) until I was back to pre-pregnancy. Yes, the flap de-flapped and the wobble went relatively firm.
My abs split down the middle, too. It's kind of gross when you can stick your fingers between them, isn't it? And my first was almost 9lbs, so considering my small build, people's eyes would bulge when they saw me at 6 months pregnant, saying, 'wow, you're HUGE! Any day now!' - ah, no, but thanks so much for making me feel like a heifer.
I had the flap and wobble again (another baby) and it seemed to be worse after the c-section with him, because my flap had a definitive point to flap-over from. Now I only have the wobble. I am doing a DVD called 'Tracey Anderson's Post Pregnancy workout' once or twice a week (as well as cardio, aerobics, ballet and pilates), which seems to be doing a lot to help the skin get back to the muscle.
If you're having problems with the flap and wobble, perhaps you might give that DVD a go. She works the accessory muscles from all different angles, 'working across the muscle fibers', as she says. Might work.