Burek on 27 June 2015
Forgot to answer the question:
I don't see a problem with any activity that involves consenting adults without doing harm to others.
So, one through three are completely fine, while 4 might also be tolerated, but keep in mind that incest was made a taboo due to a high incidence of birth defects in their progeny. So, in that case, harm could easily befall an innocent person.
5 of course is out of question, as it involves children, and they cannot enter an adult consentual relationship.
