Its a problem. If you go for half hour and its going really well you'd wish you'd booked an hour, although it may be possible to extend. However, I've booked an hour, this was with 2 girls, and ended up shooting my load after 30 mins! Still, we had a bit of a cuddle and talked about Christmas presents! Expensive discussion. A rule of thumb seems to be that the WG wants you to cum asap.
Its nice to see a girl that you've seen before as you can get the choreography right! I'm seeing my favourite tomorrow, it'll be 5 kiss and cuddle, 10 BJ, 10 RO, then mixture of CG, mish and/or doggy for 10, then cummin over her face! That'll run slightly over, pun intended!