Sounds like fun!
I actually wouldn't advise skipping lunch. Most people have an adverse reaction to eating large amounts of cum, which can be made worse if it's done on an empty stomach. Unless you've done it before, and know for certain your body can handle it, I'd suggest having a decent amount of bread or something in your stomach to help with digestion.
Let us know how it goes! Looking forward to seeing pics of the thawed cum!