When hitting your funny bone you should not cause any nerve damage or even damage to your bone.
Most people only hit their funny bone every once in awhile and they don't usually hit the funny bone hard enough to cause any nerve damage.
I've never damaged any nerves when hitting my funny bone and I've hit my funny bone more times than I can count and remember.
If you hit the funny bone hard enough then you might damage the nerve but you'd also likely break the bone as well.
It's not dangerous to hit your funny bone because when you hit your funny bone such as on a table etc you're not hitting it hard enough to cause any serious damage.
I've hit my funny bone as a toddler and young child and older kid and even teen and adult and it never has caused any problems.
I seem to have the worst luck though when it comes to hitting my funny bone because it seems like at least once or twice a year I will somehow manage to hit my funny bone on something.
I get a tingling feeling and I don't think it's very funny until afterwards but you should not suffer any serious damage to your bones or nerves from lightly hitting your funny bone.
It happens to everyone eventually.