Also, making things happen on his own is a confidence booster, so offer him opportunities to jab away:
Let him be the official button pusher. Help him push your floor number in the elevator or turn a desk lamp or fan on.
Give him toys with buttons. He'll love pressing pretend telephones and cash registers to hear new sounds or see characters pop up.
Tell him you have buttons. Bring his finger to your nose, and snort when he touches it, then let him press your mouth to make you yawn, your hand to make you wave, and your belly to make you laugh.