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1.
v.i.or t. ;to stimulate the male genitals usually by use of the left or right hand according to preference,but may also be achieved by filling a milk bottle with chopped liver and leaving it somewhere warm for several hours before use."whacking off" almost inevitably leads to the ejaculation of the male seminal fluids.These are best caught adroitly in a Kleenex.The use of visual aids is widespread.
WHACKS OFF;"you the kids that been whacking off in mah toolshed over pictures of my wife.."

WHACKS OFF;"I whacked a great one off while watching Princess Di's funeral".