
Pretty sure I'm not ambidextrous...
I hardly ever write with a pen these days, and my handwriting is appalling either-handed, but other than things like the tails on "g"s it genuinely felt more intuitive to just pick up a pen in my left hand and do mirror-writing than write with my right hand, and both felt equally back-to-front... (I do have a migraine though so that may be partially why...)
I think my 6 year old writes neater than I do right-handed!! My 11 year old is right-handed, but when she sprained her wrist last summer, she discovered that if she tries she has enough fine motor skill control to draw with her left hand (not quite as well as right-handed, but better than a lot of people can with their dominant hand)! I can throw a ball right-handed, and will switch over (my left shoulder is messed up). I tend to catch left-handed or two-handed. I'm left-foot dominant. I bat left-handed. I play tennis left-handed. I knit right-handed I think. I use both hands to make jewellery. I use scissors left-handed... I think I play pool right-handed but it's been a loooooong time...
When I've done those tests I've tended to come out like 95% left-dominant!