My foam fabric looks like this, white-pink.
Take the foam and determine DOGS line – the direction the foam stretches most. DOGS on my foam is marked with a blue line. Observe how I laid cup pieces. The foam is laid in one layer, there is no fold line.
Also, mark the notches and put a similar sign on all pieces to designate this is for R-ight cup. Also, mark where the seam allowance is, this will tell you how to arrange pieces when sewing.
Now, flip the paper pattern pieces, lay them on the foam following DOGS line.
Trace the pattern for the second cup, remove paper pieces. Mark notches and L-eft (for the left cup) and seam allowance.
We are ready to cut. Start cutting exactly on the traced lines.