NASA actually commissioned a report on ways in which this might be done, in order to determine if colonization of space habitats was to be Fun and Easy, or Sterile and Artificial. IIRC, they came up with several 'technical aids' for this activity, some of which are:

  • The Rubber Band Method - just what it sounds like, a large elastic band that holds two people together at the waist.
  • The Velcro Method - Suits with corresponding velcro surfaces on the arms and legs.
  • The Air Weenie Method - The most 'fun' or 'successful' depending on your job description. Consisted of an air-filled water-weenie-like toroid into which both people crawled, like a sleeping bag, and was then inflated to user-approved pressure; loose enough to allow various congressional acrobatics whilst still providing a means of enforcing continued contact.