How to draw inside a shape in Illustrator?

I am wondering how I can make the tan coloured lines be within the pink blob. I want the pink blob to be my primary shape, and the lines just to be decorative, within the shape, not sticking out as in the picture (it's tuna sashimi, if you were wondering). I want the pink blob to make a clean cut of all the tan lines.

I've tried using the "Minus Back" function in the "Pathfinder" tool but it hasn't worked for what I want to do. I've tried applying "Minus Back" to when the lines are arranged both in front and also behind the blob. "Minus front" does not show up as an option in my Pathfinder menu. Thanks for the help, in advance. 🙂 Have a good day!

{Renamed by MOD}