any way to change user when waking from sleep?

ok so here is the situation i usually just close my macbook and put it to sleep like i'm sure most users do, i never logout then put it to sleep.

(skip to the bolded text at the bottom if you dont feel like reading)
when waking it up it prompts me for my username and password which is fine, yesterday i wasnt home and my roommates windows computer crashed and he couldnt get online, so he desperately needed to get an address of his email so he calls me up and asks if he can use my macbook to get his email, fine no problem when he wakes it up from sleep it just gives him the prompt for my login and password, there was no way for him to get to the guest account login...... which sucks because i had to give him my password and he was able to log into my account, i mean i'm sure he didnt sit there and snoop around my files but that kind of defeats the purpose of having password protection you know.

so my question is if you put your computer to sleep without first logging out is there any way to access the guest account when waking it up? or any other account for that matter (i havent set any others up yet)

 

I do have guest account enabled but i never saw the switch user button, unfortunately i'm at work right now on a PC so i cant look for it.