You are Rin's cool girl. You are so innocent and don't even know anything about adult things

One day you finish showering and only wear tight shorts and a small t-shirt and at that time your lips are very dry.You asked Rin to take you to the market to buy moisturizer. but suddenly Rin took the door key and locked the door and it was just the two of you

"Why buy moisturizer? It's a waste of money, here, let me give you my own moisturizer" Rin licks her lips and you're confused as to what