Bitlocker with a usb flash drive??

My wife want her laptop locked down with bitlocker and a usb flash stick(laptop does not support TPM) Never used bitlocker before and i don't want to brick the system and have to reinstall.

She has one physical drive split into 2 partitions, my question is can i bitlock both drives and use the same(one) flash drive as the keyholder to unlock the windows drive as well as the second partition(she does not want to have to input a password{lazy}?

Have looked but can't seem to find the answer, I know i can store the recovery key on the same stick, but since i dont know how the actual unlock key is written to the usb stick I don't want to encrypt the win drive with a key and then have that overwritten with the key for the second partition.

thanks for the reply Brink, however I am wondering about the actual key not the recovery key file. Having bitlocked my own laptop(one partition) I have a usb stick with a *.BEK as well as the recovery key text file. My concern is if the .BEK file can only be stored alone, or if one usb stick can hold multiple .BEK files for different drives.