There is actually a new app for legally binding consensual sex. For Real! Legal Fling is a new app allows you to formally have consensual sex. (Daily Mail)
Live Contract is only shared between the parties involved, and is placed in the blockchain, which is a list of records, called blocks, which are linked and secured using special encryption.
Users can change their mind at any time and being drunk or passed out means no any time, written in the terms of the agreement.
You CAN withdraw consent through the LegalFling app singly.
If there is any breach of contract, the app claims users can use a cease and desist letter with penalty payments,' and make it easier to bring the case to court.