I have a friend whom, when I kiss her, I feel lust. What should I do?

Any unnatural inclination, even from a female towards another female, is forbidden. One must avoid its inducements. What you experience in terms of desire towards your friend when you kiss her falls under this category. Therefore, you must content yourself with shaking her hand, without kissing her, to cut off the root of evil. Some scholars have prohibited kissing, while others have deemed it reprehensible, basing their opinion on a hadith (definition) where the Prophet, peace and blessings be upon him, was asked: "Should a man bow to his brother when he meets him?" He said: "No." He was asked: "Should he embrace and kiss him?" He said: "No." He was asked: "Should he take his hand and shake it?" He said: "Yes." Narrated by Ahmad and Al-Tirmidhi.