The [sysReq] key is usually on the [Print Screen] one, and it's
holding down the [Alt] key that activates it.

R E I S U B refers to the keys on the keyboard, pressing one at a time
and then pausing before pressing the next in the sequence.

There are a few acronyms for remembering the key sequence:

Raising Elephants Is So Utterly Boring

or make one up for yourself that you'll remember