Topping rhymes with:
stopping, chopping, copping, cropping, dropping, flopping, hopping, lopping, mopping, popping, propping, shopping, sopping, stopping, swapping, wapping, whopping
Topping sounds like:
tabbing, taping, tapings, tapping, thieving, tiffany's, tippens, tipping, tippins, toobin's, topanga, toppings, toppins, tubing, typhoons, typing, typings