Euphemism for having sex. The expression came about because the sound made while nailing a towel rack sounds a lot like the sound of a headboard banging against the wall during sex. Also, see "nail."
To hang a towel from ones erect penis while waiting for the personin the shower to reach for a towel, but results in the person reaching out getting a dick and a towel, and usually results in sex at the end of this dick grabbing experience.
after jane was done showering she reached out for a towel but instead got a towel and johns dick. Jane just got ikea towel racked, and john got laid.
A male wears a towel tied in the back. He then gets an erection. Upon releasing the towel it stays supported by his erect member.
After skinny dipping in the Scotia Towers fountain I was mortified when my friends tried to whip off my towel and I was left with a Whalley Towel Rack.