Soap on a rope can also be a gag gift for someone whose activities lean towards the illegal. The innuendo is that if or when the recipient winds up in prison, he can use the soap on a rope in the shower. This lets him avoid dropping the soap and having to bend over to pick it up.

(If you haven't figured it out yet ... bending over in a prison shower is reportedly not a healthy activity, particularly if the burly guy under the next spigot over has been washing it as fast as he wants ...)