These rules are especially important when passing backstrokers. They cannot see, so make certain they know where you are. However, all swimmers must be considerate of this fact. Faster swimmers must realize that slower swimmers are trying just as hard as they are and that their set is just as important. Slower swimmers must understand that it takes a toll on faster swimmers to have to pass you constantly.
Touching feet is a no-no.
Swimmers who swim on another's feet are annoying at best. Leaching, or drafting as it is called in cycling, is also a big no-no. Passing should always be done on the outside. If you pass on the inside there is no room for the passee to go. By moving over close to the lane line, by obeying turn rules, and by using the space above the black line for passing only you will facilitate workouts for everyone.