I need help with my dog...

My dog pees on my bed.. randomly, no specific events trigger it. I changed the sheets today and I guess she did not like that because when I came to be there was a wet spot on my comforter. Can anyone tell me why she does this or what I can do to stop it?!?! It's infuriating!!!

Info... 3 year old beagle. Super energetic. Spends a TON of time outside (as much as she wants weather permitting). It seems that she likes to pee on the beds and I think she peed on a couch throw pillow once.

Here is a pic of the super misbehaved girl...