Justin and I watched multiple youtube video and they all had very similar qualities. They all over stressed their vowels to the max. It was incredibly peppy and somewhat smooth, but you could tell it was improvised. When we filmed our intro, we did the most basic, typical youtube intro you could think of. We were also super peppy, we stated our names (Justin even used a nickname), and we stated where we were and what we planned to do. I tried to do the sneaky extra vowel, but it was really hard to think of a word where I could do so. The one thing we did that is extremely common is ask everyone to like and subscribe whilst pointing at the bottom of the screen.