In a typical tummy tuck (abdominoplasty), the skin and fat of the abdominal wall is lifted up off the rectus or "6-pack" muscles. Some of the blood supply known as the lymphatics are temporarily disrupted. This allows fluid to build up after surgery.
The fluid needs to be drained to avoid a collection known as a seroma. I will typically keep a drain in until less than 30ml of fluid comes out per day. Being overactive when you are supposed to be taking it easy can increase the chances of a seroma.
Most surgeons have their patients wear an elastic abdominal binder (like a soft corset) after surgery to try and push the skin/fat back down onto the muscle layer and prevent any deadspace for fluid to fill into. Also, avoiding a lot of trunk twisting in the first few weeks after surgery helps.
Liposuction is often combined with abdominoplasty to accentuate the results but the risk profile increases. Speak to your surgeon candidly about this to be well-informed.
I appreciate your fears about abdominoplasty, but if you truly need it you will end up loving how it looks. If you are afraid of the pain after surgery, ask your surgeon about a pain pump. A pain pump is a small device that delivers a constant stream of numbing medicine (eg. Marcaine) through a tiny catheter placed under the abdominal skin. It typically stays in around 5 days and can make the first few days after surgery much more comfortable.
Good luck.
