If you connect with the person and you become friends, then you will not even need to ask. For example, after you get to know the person your comments will be different. Say I become a friend of my roommate. And then after a month or so, he brings a refrigerator. I wouldn't ask to use it, I would rather comment on how useful it will be. It's assumed that a friend can use the refrigerator, so no need to sound weird by asking politely. Instead you can say,
This comment is saying that you appreciate the refrigerator by saying, 'cool', then you indicate that you are going to use it by saying you will buy milk. If your friend doesn't object to your comment, then it is the same thing as getting permission to use the refrigerator.
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