It is odd that neither the Church nor modern public opinion condemns petting, provided it stops short at a certain point. At what point sin begins is a matter as to which casuists differ. One eminently orthodox Catholic divine laid it down that a confessor may fondle a nun's breasts, provided he does it without evil intent. But I doubt whether modern authorities would agree with him on this point.

An Outline of Intellectual Rubbish: A Hilarious Catalogue of Organized and Individual Stupidity (ed. 1943)