My son is two years old and snuck behind me as I was brushing my teeth to flush a tangerine down the toilet (he has figured out how to open the safety device we have on the toilet). No water is backing up in the shower or the sink, so from research it-it means that it isn't stuck too far beyond the bowl, right? We've tried plunging and of course that will not work.. How would I go about removing the tangerine? Or should I just call a plumber?

And I truly do not feel that the sulfuric acid is safe at all, so I do not even want to use that.

Can you get to the plumbing below the bathroom? Is there a cleanout plug?

So water is backing up in the toilet ?

If so, yes, it is very likely stuck in the "U" of the toilet itself, If it is, the toilet will have to be taken up from the floor and the object removed from the bottom side ( and it will not be easy)

If it is in the actual drain pipe, I agree, if there is a basement or crawl space, there should be a clear out for the toilet

I mis-read 'no water is backing up' as 'now water is backing up.' What is your evidence that it is still in the toilet?

Every house should have this tool,(see image), This is a closet auger, Auger the bowl and if you can flush paper down then it's clear, Good luck and NEVER use any acid to clear a clog. Good luck, Tom

Maintenance came, use that toilet auger and I think she made it worse! Before, water flushed and went down. Now, it just fills up to the rim and then slowly seeps down. Should I give in and use sulfuric acid to disolve the tangerine? Or call the plumber? She said the toilet will qprobably needs to be replaced. Everything is underground, no crawl space or acess to the piping.

Don't pour anything down a toilet that isn't specifically designed for toilets. You will destroy the porcelain glaze and endanger your safety as well.
The auger probably drove it to the second bend. They need to come back and keep working on it (unless it rots just enough to go down by flushing or the plunger).
I see no reason to replace a toilet because of a tangerine. The next step would be to take it off the floor and clean it from the underside.

Awesome! They sent a different maintenance man, and he kept using the toilet auger and pushed the tangerine through. No chemicals used at all! Nice and safe for the ocean :) Thank you guys for all the advice and since of sanity! Lol

And we thank you for the update. From on let the kid play with fruit that's too big to go down the potty, Cantaloupe or watermelon come to mind, Glad you're all fixed up, Good luck, Tom