Hush Up

I was humming a Carnatic song while dialing my friend’s number. The phone rang for long and I continued humming. All of sudden my friend picked up the phone and I never realized it, as I was totally enjoying the tone. He maintained his silence and never responded back with usual hello. He heard me humming and at the same time I too realized that my friend had picked up my call. He said continue humming, why you stopped. This is the second time I have experienced such a thing with the same friend.