You can also just create a private room and both join it.You can also invite them via Facebook invite if you both are friends and using the Facebook version.You can also invite them by email granted they entered their email into their Cribbage profile settings.Then go to Online-> Play a Friend-> Invite Code

You can find your Invite Code / cribbage ID by clicking on your profile, or going to the online game and it will be in the upper right hand corner. The best way is to add them by their Invite Code / cribbage ID.To play a friend do one of the following: