We have a very loving five year old female Dacshund. She has been fixed since very young. However she loves to hump our arms at times and she licks our arm while doing this.
While this is quite amusing we wonder why she does this. Does anyone have any thoughts?
Thanks

They do it for various reasons. To show they are boss, independent, territorial, affection,

Our female beagle went after our bed pillows to hump on every chance she could get.
If we went in the bedroom and found the pillows scattered around we knew what had been going on. She was neuered but some primal urge was coming through we figured.

I think your amusement when she does this, might be understood as encouragement. Laugh afterwards, but when you can tell she is going to do it, give her a sharp NO, so she will understand that you are the boss. Don't worry about hurting her feelings, she will get over it, and understand that there are boundaries... just like children have certain rules and boundaries. :)