The inability of having sexual intercourse when traveling, out of a sense of not being in familiar territory, or having an in-law walk in on the act, or out of the grossed-out notion that you are being eaten alive by bedbugs.
Often this occurs during holiday travels when visiting family, out of the sheer horror of having your mother-in-law (or biological family member) detect the act in some way.
What's wrong with Joe? He seems kinda stressed out.
Sextipation. 'Nuff said.