So I noticed once upon a time, while defending Jerusalem from a Jihad that I was getting a +75 vassal opinion bonus from defending in a holy war.
This came in handy when my character died and was replaced by his son in the middle of said war. Instead of panicking about huge negative opinion vassals due to short reign or pretender status, I just carried on with the war with all my vassals content. It was a long bloody war and by the time it was finished my short reign negative was gone and I'd arranged for several "accidental" deaths.
Later, while sieging my way through a militarily broken France on a conquest war the Muslims attacked again. While I did have to divert some of my armies, my vassals who were grumpy after such a long war in France, all of sudden were happy again. I could finish off France without threat of mass revolt back home while my split army combined with every other Christian nation who lept to my defence dealt with the jihadis.
QUESTION is, as I quite LIKE it when the infidels attack, giving me a huge vassal opinion boost and thereby room to breath, is there any way to goad foreign powers into attacking you at a politically opportune time? Any way to insult them or perhaps fail assassinating them on purpose?