My sister is at an age where she is concerned about her figure, so she started exercising at home to lose weight! Although she tries her best to restrict her diet and exercise, she is stressed out by the sudden diet and is irritated every day. However, the clothes she wears while dieting are very sexy and focus on ease of movement! I had never noticed before, but my sister's breasts are surprisingly big, and they are shaking all over the place! What's more, if you look closely, you can see her nipples through her sweat! Seeing her like that, I get an erection and my sister finds out, but she grabs my dick to relieve stress!