you need toys and a blindfold
Have your child sitting on a blanket where he can see his toys. Pick up one toy and say “now feel your bunny darling” guiding his hands over a soft toy “feel how soft and fluffy this is”. Take a block and say “feel your block, notice how rough it is” and so on, letting him see, so he will start to connect the sense of touch to what he is seeing. After this process, blindfold your child repeating the same process in the same order, naming the objects. After that say “now keep your blindfold on and mummy will give you a toy without telling you which one and you have to guess what you are feeling without looking”.