lay something alongside (of something)
to place something next to something else, lengthwise. (Of is usually retained before pronouns.) Please lay the spoon alongside the knife. Find the knife and lay the spoon alongside.
lay alongside something
[for a ship] to rest afloat next to something. The ship lay alongside a lovely island while a shore party searched for fresh water. Our ship lay alongside the narrow wooden pier.
lie alongside (of someone or an animal)
to lie next to someone or an animal. (Of is usually retained before pronouns.) Jimmy came in to lie alongside of his father in bed. The puppy lay alongside its mother.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.