Love carries many types of expressions, most of them explainable, some others questionable.
Some people like to take a small bite as a show of affection, even if it sounds weird, it’s true.
Whatever the situation that is presented as an expression of love, the reality is that love involves precisely many expressions of affection.
That love moves us to give gifts, to give cuddling kisses or a small and sporadic bite.
Your partner is not crazy, or out of it, it is just one more of his ways of expressing love for you.