This was one of my grandpa’s favorite jokes. Not sure how many times I heard it:
A woman tries getting on a bus but realizes her skirt is too tight. As the bus stopped and it was her turn to get on, she became aware that her skirt was too tight to allow her leg to come up to the height of the bus’s first step.
Slightly embarrassed and with a quick smile to the driver, she reached behind her to unzip her skirt a little, thinking that this would give her enough slack to raise her leg. She tried to take the step, only to discover she couldn’t.
With a little smile to the driver, she again reached behind to unzip a little more and was unable to take the step again. After becoming quite frustrated and embarrassed, she once again attempted to unzip her skirt more to allow more legroom to get on the bus’s first step.
About this time, a large Texan who was standing behind her picked her up easily by the waist and placed her gently on the step of the bus.
She went ballistic and turned to the would-be Samaritan and yelled, “How dare you touch my body! I don’t even know who you are!”
The Texan smiled and drawled, “Well, ma’am, normally I would agree with you, but after you unzipped my fly three times, I kinda figured we were friends.” 
