She peed on the couch again:/

Hi,
In a previous thread I mentioned how Sophie peed on a blanket on the couch. Well today she did it again. The first time she did it was after my husband petted her and she was very relaxed. It sort of happened the same way this time too. She sat beside me on the couch, which this is the first time she's done that, then she closed her eyes and was tooth purring. She sat for awhile like this then got up and jumped off the couch. I had no warning at all this time and in fact I didn't even know she peed until about 30 mins later when I noticed it. Needless to say, the pee went straight through the blanket and on to my brand new couch:cry4:
My question is, is this normal for them to pee while they are being petted? The whole thing was just weird to me and I really hate that this happened. Not because of the couch, but because she was being so good lately on the couch and it was appearing like the first time was an isolated incident. The worst part was that I didn't notice it when it happened so I had no way to deal with her constructively with it.

I continually find my buns like to pee on soft things. I don't like to let Ripley jump on the couch unless I can be continually watching him well. He doesn't really ever have accidents out of his cage, but 2 of the 3 or 4 times he ever has has been right there on the couch.

I tried letting my guy hop on the couch, then he peed all over it. I put a plastic shower curtain over the couch, he hopped up and peed all over that too. He is no longer allowed on the couch. >.<

My rabbit used to pee on the couch (or on me sitting on the couch) every time. He has since stopped. I don't know why he stopped, but he hasn't done it in months. Which is nice, for cuddles.

Some do and some don't. We considered all the furniture in the family room to be "sacrificial" which is why it went into the dumpster when we moved.

They like to mark the things that smell like YOU with pee that smells like THEM. Foo peed on the couch a few times.
Plus, I think they like to pee on soft things, I think they like soft things on their feets.

So does anyone think that petting them and relaxing them increases the likelihood of peeing? Or was that just a coincidence?