Waiting until you're exclusive to have sex is too old-fashioned of a maxim to work for everyone, but there are other things that should happen only after you're committed...
1. Friend each others' friends on Facebook.
2. Stay in each other's bed/apartments while the other leaves for work.
3. Going to each other's work functions.
4. Ask each other to pick up anything remotely health related (tampons, sinus medicine, birth control, foot cream)
5. Have nights where you stay in and just watch tv.
6. Pee with the door open. (Or never! Never is also an option for this one!)
7. Introduce each other to your parents.
8. Make plans more than a week or two in advance. (Aka booking concert tickets for three months from now.)
9. "Pop by" each other's place of work, unexpectedly.
10. Each other's laundry.
Via The Date Report