My mommy friends toned their tummies by doing core strengthening exercises like planking after they feel that their bodies have healed. They would plank (yoga plank or elbow plank) for 30-60 seconds everyday. None of them used toning creams but the planking coupled with their busy schedules and healthy eating seems to have worked. Other post pregnancy core strengthening exercises you can try include pelvic tilts, side planks and yoga boat. Here's a youtube video that demonstrates such core strengthening exercises for mommies: https://youtu.be/Uxz0A9EyvWc
I generally do not believe in those toning creams; they seemed to gimmicking and carries tons of over promises. Like Idza has mentioned, the most effective way is through the old fashion way of exercising. For me personally, aside from watching what I eat, I climb up stairs halfway to my house (I live on the 9th floor) and exercise pretty regularly at home. Most of the time I use my son has my weigh since he's about 10kg. To date, in about 3 months, I've lost over 10kg ☺️