It is, however, a mistake to conflate ad baculum with threat and intimidation. The original point, of course, was just a joke -- 'Here's my argument, the stick' -- but Isaac Watts had recognized that these kinds of labels, like ad verecundiam, were topoi or commonplaces, strategies for picking a middle term for an argument, and for the same reason, it is certainly the case that if we are to take ad baculum as a serious label, it has to cover something like this. There is indeed a kind of argument that has occasionally been called ad baculum that fits the bill. Three examples I have noted before;
Brian Magee on free will (Confessions of a Philosopher, Random House  p. 152):
I am entirely confident that if you subjected any determinist who is not a psychopath, however amoral his life, to outrageous and cruel ill-treatment, he would become indignant with you and protest that you ought not to treat him in that way. Ought and ought not would spring to life for him then, and he would insist on attributing to you the ability to behave otherwise.
Scotus on contingency (Reportatio IA prol. q. iii art. i; in Philosophical Writings, Wolter, tr., Hackett  p. 9):
And so too, those who deny that some being is contingent should be exposed to torments until they concede that it is possible for them not to be tormented.
And, of course Scotus is adapting Avicenna on noncontradiction (ibid., with a minor change):
Those who deny a first principle should be beaten or exposed to fire until they concede that to burn and not to burn, or to be beaten and not to be beaten, are not [the same].
None of these, incidentally, are fallacious -- the baculine link in each case is relevant and appropriate, providing a legitimate way to reach the conclusion drawn (in all of these cases, that a particular position is not something anyone can consistently accept). Any number of other things could in principle work in the same way, and be recognized as nonfallacious; the baculinism is a rhetorical choice that does not affect the basic functioning of the argument.
This relates to the second conflation that has often confused matters in discussing ad baculum arguments; namely, the failure to make a proper distinction between the argumentative move and the rhetorical approach taken in making that move. Ad baculum, like ad verecundiam and similar labels, designates a rhetorical approach exemplified by the link that constitutes the argument; as with those other labels, there is nothing intrinsically fallacious about it. One gets an ad baculum fallacy when one commits an argumentative fallacy that happens to be in ad baculum rhetorical dress. The actual fallacy will be something distinct -- ignoratio elenchi, in fact, which is why ad baculum, when classified as a fallacy, is always classified as a fallacy of irrelevance.