If you didn't Cum, it didn't count. Therefore participating in sexual activity when in a relationship without cumming is not cheating.
John: "Man, she sucked me up last night"
Tim: "So you cheated on your girlfriend?"
John: "Naw, the Joseph Rule was in effect."
Tim: "So you cheated on your girlfriend?"
John: "Naw, the Joseph Rule was in effect."
by Wrist Band Man December 11, 2010