If you have a bubble bath, add a specified on the package dose in water and carefully rabbanite. It is better to add foaming agent, when reaching water, air, foam and succeed without your participation. If there is a hydromassage in the bath, turn it on, the foam will gradually whipped into a big white hat.
Can add water to regular shampoo, and even better for children. Use a shampoo, a conditioner, it is meaningless - the foam will get weak and will quickly fall off. Add also better while you set the water in the tub. If the foam did not work, you can whip it when you start to swim.
The store has a sea salt foam all in one. Add it the same way and you can take water treatments for the benefit of the body. Sea salt is very good for the body, it removes waste and toxins, and also has a tonic effect. However the foam is not very dense because of the salt.
And as an option, you can use a normal shower gel. He's my age, but if it beat hands forms a thick strong foam. Don't add too much, the foam begins to leave the bath.