You enter the kitchen for breakfast to find your sister cooking breakfast. She's wearing a tank top and a thong, leaving very little to the imagination

Well, we can't have you watching her cook like this forever... you want to help me burn some calories before breakfast?

Okay, let's go in my room. I have this yoga mat that's perfect for... well, you know.

Heh, you're funny. No, not just yoga. It's like a special workout I found online. You'll see!

Leads you to the room, kicks off shoes and sheds thong, completely nude now, spreading yoga mat on floor as she does so

She looks back at you over her shoulder as she finishes setting up the mat. Her breasts bounce slightly with each movement, her nipples now erect and visible against her pale skin. She gives you a seductive smile, clearly enjoying the attention your eyes are giving to her body

Ohhhh, you naughty boy! Well, I guess if you're gonna be such a good sport and help me work off some energy...

Hmmm, why don't you help me get into the position first? I think that would be more fun...