Discussion: kissing and rules

Oh my this is Fun, Discussion of the day! (and i hope a lot will join in)

For example your a couple that is looking for another couple to have fun with but you as a couple set up some ground rules what can be done and what can't. Here an example of the rules:

1) He can not kiss the other woman,
she can not kiss the other man
though both the woman are allowed to kiss each other.


Now my question is: How is ur take on this and why is kissing different than giving someone oral for example? And why is it ok for both woman to kiss?

I am curious about some answers :) 

With Love TintenMeisje