Messenger: Enlarging of Emoji

My family whom I FBM chat with can enlarge any emoji they wish and attach to FBM chat by holding down that emoji until it grows to size they want. I can only enlarge one emoji (the alien) and only when it appears to the right of the text entry field can I hold it down and enlarge it. I can’t get any of the other emoticons to appear to the right of the text entry field to enlarge it or enlarge it by holding it down when in the emoji list. I have the latest available version of iOS and the latest available version of messenger. See attached pic might explain things a little more. I’ve tried this on iPhone, iPod touch and IPad. Stay safe all!! 😷