To think my friend overreacted? Air BNB situation

because I had just checked/cleaned the bathroom upstairs and didn’t want to have to do it again.

Youve just communicated to her that you don’t think she’s capable of using a bathroom and leaving it in a clean, sanitary state.

I wouldn’t be going to Costa again with you, let alone away on holiday.

100% of responses are letting you know that you have been unreasonable but you are clearly unwilling to see this. If you can't understand that you owe your friend an apology for your strange behaviour despite everyone unanimously agreeing that that is the appropriate course of action, then it is clear that you are the problem.
Has this kind of behaviour caused issues anywhere else in your life? Have you lost friends before over similar encounters? It might be worth having some self reflection. Try to ask yourself why you needed to exert strange controlling behaviour over a grown adult. Really put yourself in her situation and ask yourself how you would feel if someone told you that you weren't allowed to use the bathroom you wanted because they thought you would leave it too dirty. What a horrible position you have put your friend in.
I'm not sure I would want to be around said "friend" after that too.

I don't understand why it matters which toilet she used - they were both part of the AirBnB property and so either one of them being left dirty when two of you left could have been a problem. Was it just that you didn't want to go back upstairs and it would have been easier for you to re-check the closer downstairs one? I'd have sucked up the slight extra hassle, under the circumstances.

Perhaps she thinks you were being weird or rude assuming she would leave either toilet dirty after a last-minute use. If that's it, I'd just explain to her that you always feel like you have to inspect the entire property immediately before leaving so that you can authoritatively argue that everything was in order if the owner questions you (and it will be you because it's your account). I can understand why she might not have understood this based on what you said, which comes across as brusque and bossy the way you've written it here.

Can you just ask her what's wrong? Maybe these trips would be easier if you had your friend make an account and used hers, or took turns?

Wow yes YABU

Putting the toilets and beds aside @userfriendly55 unfortunately you sound very selfish. You spoke to your friend like she was a child. I get that it’s YOUR Airbnb account but she has paid half, she can use the other toilet on the way out if she wants. You act like you are doing her a massive favour here, ANYONE can make an Airbnb account!!you were rude and you know it.

My friend said she needed to use the toilet before we left and went to go upstairs. I asked her why she was going upstairs, and she said the downstairs toilet wasn’t flushing properly, and she was on her period. I told her not to go upstairs because I had just checked/cleaned the bathroom upstairs and didn’t want to have to do it again.

Yeah you’d no longer be my friend if you treated me like this.

I don't think you're expected to obsessively clean these places. Even if they don't have a professional cleaner, so what? If you'd just cleaned it, I doubt it would need cleaning again after one use.

Yes, you probably offended or annoyed her. It's funny that you think she overreacted when you're the one who essentially told her she couldn't use whichever toilet she preferred. People tend not to like that. Now you know.

There isn't always a cleaning fee at all. Some places charge one, but it's very much optional as a host to add a cleaning fee and many don't.

Well then you owe your ex friend an apology and you also owe her money.
I'm actually thinking this is a reverse as no one could possibly be this entitled

This is so weird. OP, you’re unanimously being told YWBU but you’re doubling down.

Is the real issue that you’d left a lingering smell and didn’t want her to notice? Or do your toilet visits make a terrible mess and you were projecting that onto your friend, thinking she’d do the same?

If she was going to use a toilet, why did it matter to you which one it was? And why did it matter enough that you had to belittle her like this?

Yes.

Whether or not they choose to use a professional, there is always an absolutely massive cleaning fee. The expectation is to leave it tidy, not properly clean everything! OP you are the only person I’ve ever heard doing this.

also YABVU both about not saying to pay less for sofa bed (I don’t have a health condition but they are usually bloody uncomfortable!) and to tell her which toilet she could use.

Of course people should leave the toilet clean. I've marked someone 3* for cleanliness because he left the toilet full of skid marks. But WHY did you assume your friend would leave the toilet dirty? Does she have form for it? She was offended that you suggested she would leave shit or blood in the toilet bowl. Why did you assume she would?

Surely you wouldn’t leave ‘shit stains’ in a toilet for someone else to clean?

YAB so extremely U.
That would be the last time I’d be going away with you.

This is one of the strangest friend to friend relationships I've ever seen.

I'm almost expecting a drip freed that you're her mum.

It sounds like she’s let your OTT cleaning slide for a while and now this toilet incident has finally pushed her over the edge. You’ve been completely bonkers.

YABU, you are controlling and unpleasant.
You also got a good deal, your friend sounds lovely I hope she is offended enough to ditch you. She is better of without you.

This. So weird. And why are you cleaning them, you pay for that. Just leave it clean and tidy, but no need to actually clean. And how disgusting are you and people you know if they can't use a toilet without leaving a mess? I don't even really understand this.

Yabu. Why would you scrub an airbnb? There is a cleaning charge included.
Tidy, yes.
can’t believe people wouldn’t clean the loo in an Airbnb - not even if you were on your period or had the shits??
Do you not flush once your done.

You were completely out of order and frankly rude, your poor friend.

How controlling!You had no right to behave like this! That would be the end of you being a friend of mine.Utterly ridiculous.

YABVU but you don’t seem to be listening. I doubt your friend will wish to go away with you anywhere again so don’t worry about it.

I often shared an Airbnb which I booked on my account with friends and never had the urge to check the toilet after them.

thats really weird and comes across as if you think she’s a slob or you are a control freak. Would keep my distance too.

You know the disability benefits are meant to cover the extra costs associated with being disabled, for example, paying a larger share of accommodation costs on holiday when you are going to automatically take the best room.