i really don't think they plan that part, definitely ad-lib especially judging from Yunho reaction he totally did not expect Changmin to take that gag that far lol xD
seriously Changmin is really unpredicatable, he is the one against this gag in the beginning and Yunho only making this gag really cute but once Changmin decide to turn the table and making it Minho version, the Bibarui gag keep on getting more and more intense and sexy while Homin version is more cute childish like...
but Minho version is totally dangerous since Changmin is in full seducing and attacking mode making Yunho kinda restless and caught off guard everytime because he himself like all the fan don't know what move Changmin would do next lol :P
and the last day is the best one because Changmin taking the gag into whole new level maybe because that is the last one so hi decide to do full force fan service :P

seriously i am really curious with what in that boy head, he of all people always against doing fan service like this and he really didn't have to take it this far as well since he doesn't seem to mind to not listening to fan request and can make them shut up anytime but why he instead is the one initiating this and seem too excited for this lol :P
like during 1st day Tokyo Dome seem like Yunho don't want to do the gag anymore maybe because the ir parent is there but Changmin is the one suggesting they do it..

ahhhhh seriously even if i don't want to ship them more than brother but kind of thing really make me hard to resist this pair especially Changmin seem more open nowadays showing his love to his hyung while Yunho adoration for him is the ost obvious thing in planet earth :P

lol now this become like essay :P
yeah really want to know what type of convo they have after that lol :P