ما حدود تقبيل جدة زوجتي للسلام؟

There is no harm in kissing the wife's grandmother and other such mahram (unmarriageable relatives) if there is no fear of temptation; otherwise, it is forbidden. The kissing should be on the forehead or the head, not the mouth. Ibn Mansour said to Abu Abdullah: "If he returns from a journey and has no fear for himself, he should never do it on the mouth, [but rather] the forehead or the head."