How do i go about asking for a spanking?
The easiest way is simply to ask. However, if you are too shy to put it into words here are a few ideas.
Text or email Him. Sometimes it is far easier to type out what you want and hit send than to say the words while looking into His eyes.
Leave a note. This feels more personal while still allowing you to not have to ask for it to His face. There is also the potential for all sorts of games when notes are involved.
Then of course there is the wonderful option of being on your hands and knees, ass facing the door, with a paddle balanced on your ass when He comes through the door at the end of the day.
Too each their own of course. ;-)