LOL! Well I only use a child size toothbrush, it's the only kind my dentist gives me bc I have a small mouth and it gets in the crevices better for me ;)
I also have a small mouth lol! I use adult sized toothbrushes. I got electric toothbrushes online for cheap. I have 2 that work but can't find brush heads without ordering a whole kit. At least I know what to do with a brand new electronic toothbrush.