My pups developed a habit of peeing on the bed

Question
I live in a large studio and have 2 lab pups, one 6 months, the other 5 months.  I've been very dilligent about taking them out.  I keep them in their crates when I can't supervise them.  I take them out 5x a day since they are puppies.  They don't pee or poop anymore on the carpet but...

Howver, there is one bad habit I am having difficulty to break.  I don't let them on the bed and they know they are not suppose to go on the bed.  However, about 2 months ago, one of them went on the bed and had a pee accident and since then, they think the bed is a potty place during the off schedule times they need to go potty.  They are pretty sneaky about it too.  Because when I am not looking, that's when they go on the bed.   And I am not talking about leaving them for long hours, I am talking about stepping to the kitchen or answering the phone etc.

I've already thrown out my bed because the smell is impossible to clean.  I have been sleeping on an airbed these last two months and they still pee on the airbed as well!  At least it's easy to clean but it is getting very annoying to keep washing sheets or to finally go to bed and feel it damp.

I am trying to catch them in the act of doing it but I haven't because they don't go on the bed when I am around.

How do I break this habit?  I am almost at my wits end!

Answer
Hi,  Well I have heard of this before.  This is pretty serious and very disheartening for you.    Lets see if we can try a few things.  Believe it or not this is a compliment from your dog, but who needs it!   They are claiming you as theirs.
First:    Go to the store and get a "keep away" spray this could be bitter apple or something that discourages peeing in certain places;  spray your bed frequently.
Next is an old remedy that is not exactly approved of anymore, but I find it still works on certain dogs in certain situations.   When you find it wet bring over the culprit (you can see who is wet below) and stick their nose in it saying very sharpley  No No potty ! Then bring them outside and when they go say good potty.
Also get a mousetrap and put it under some papers so when the dog jumps on the bed the mouse trap goes off and scares them.
also  there is in some of the magazines  a pad that gives a very mild shock and vibration if the dog goes on the bed.  If you can eliminate them going on the bed this will solve most of the problem.  It can be left on the bed. just remember to not sit on it yourself without turning it off lol.
also  when you walk them buy a back pack for each dog and weight it down with bottles of   water.  Let them go potty and then take another half hour and walk them at your side so you instill in their brains that you are the boss.  If you put some water bottles in the back packs they will get more exercise in the same time period.  It will tire them out more and they will be more co operative.   when you come home and are going to let them run around, clip a leash to your belt and to them and keep them with you.  you may have to do this one at a time to keep from getting tangled, but this will give you control and you can discipline them with a snap and harsh work everytime they even look in the beds direction.  They should not even be allowed to think about the bed much less get near it.
nancy