How do I train my nail beds to become shorter?

Just what the title says. Can I train my nail beds to become shorter? If so, how?

My GF who has been a manicurist for almost 20 years says you can't.
You can just keep your nails as short as possible or cut a 1\4 inch of each finger. Nail biters have created shorter beds through years of neurosis.

After climbing on sandstone a number of years, my nail beds do indeed seem to have receded. When I climb a lot, the nails get worn down to below the nail beds and don't seem to come back all the way. Just a thought.....