When two people, be they related or otherwise, attempt to hug but instead knock their heads together, in extreme cases, female victims of the clug yell loudly further embarrasing any male clugger.
Another word used for semen (or jizz and cum). Many people use this term when the cum is over the top, and very thick. If you were to be ever be clugged on ladies, you know you’ve gave him the time of his life.