If he's a respectable decent guy, just ask him staight out about it, and he may give you an answer- if he doesnt, he is clearly uncomfortable with this.
Next time that happens ask "whats wrong?" or reassure him that it'll be alright. Who knows, he might even come to like kissing you, with a bit of practice~ [ soph0900's advice column | Ask soph0900 A Question ]
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