guys, i want cari 1 gadget, wonder got such things bo

ok, the story is , i am driving, my phone was mount on the phone holder. a wechat/whatsapp voice message came in. I want to listen to it, so i press the play button on the phone, since it's just 1 touch, so ok la

then i want to reply with a voice message, but i need to hold my hand on the phone as long as i am replying.

any gadget that is small, can let me press it on my hand and it automatically can record my voice, and when i let go, it sent the message?

or i need smartwatch for such thing =.='