One of the most common things that I run across when either directly discussing political philosophy or reading others discussion of it is the conflation of libertine with libertarian, especially, but not only, among conservatives. However, they are by no means the same and should not be treated as such by anyone that considers themselves to be informed.
When I hear the term libertine, it is not great libertarian thinkers such as Bastiat, Rand and Mises that come to mind. Rather I think of people such as the Marquis de Sade, Ami Perrin or John Wilmot. I think of rejection of imposed religious morals and sexual freedom exercised to the utmost extremes.
When I hear the term libertarian, on the other hand, I think of personal freedom from government coercion and laissez-faire capitalism. I also think of personal responsibility. To be sure, I see how it could be easy for those opposed to ideas such as the legalization of drugs and prostitution to confuse libertarian advocacy for the legality of such things for libertine philosophy, but only if they were not being intellectually honest with themselves.
The fact that a libertarian may call for legalization of such things does not mean that he is rejecting social standards, it means that he is rejecting the forced implementation of those standards via government coercion.
To be sure, there may well be libertine libertarians, but the two are distinct philosophies and should be treated as such.