suck in

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb idiomatic To cause someone to become slowly more and more involved in a business or situation that is often not to that person's liking.
• verb idiomatic To contract one's abdominal muscles to make one's stomach look flatter.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb draw in as if by suction
• verb attract by using an inexorable force, inducement, etc.
• verb take up as if with a sponge