code:

nomad_subjugation = {

				[...]

	on_success = {

				[...]	

		FROM = {										
		# ENGLISH: 'FROM' is the guy you targeted when you declared a war.

			hidden_tooltip = {		
			# All this poo poo /isn't/ shown in explicit detail when you hover over the CB.

				set_defacto_liege = ROOT
				# 'ROOT' is you. This means that FROM (your enemy) now has a liege: you

				any_demesne_title = {
				# this checks all titles that FROM (your enemy) has

					limit = {							
					# 'limit' refines the search, so within the any demesne titles FROM holds, only...

						higher_tier_than = ROOT
						# titles of a high ranker than what ROOT (you) control are valid.
					}
					ROOT = { grant_title = { target = PREV type = invasion } }
					# any title of a higher rank than what ROOT currently has is now granted to ROOT

					add_pressed_claim = PREV
					# little flag is added saying that a claim was pressed on that title

					set_character_flag = had_higher_titles
					# a flag is added to FROM saying that FROM used to have higher titles than ROOT.
					# There's an extra bit in the CB after this which re-states 
					# the set_defacto_liege thing so that FROM definitely becomes a vassal of ROOT
				}

				[...]
			}
		}
	}
}