see the picture sleeve here). For all I know the original B-side seems to have been »Baby What You Want Me To Do« (a cover of Jimmy Reed's 1959 hit), and it is explicitly mentioned as flip in the Billboard issue of January 23, '65. Today, copies with »Jerk Loose« tend to be more commonly around, however.
»Baby What You Want Me To Do« is one of the primordial r&b duets from the '60s. Being released in the middle of the Beatles-mania (and contemporary with, for example, Elvis's pitiful »Do The Clam« or the Supremes' »Stop In The Name Of Love«) this record was the ultimate reminder of what r&b was all about when a record company did not look desperately for pop appeal but cut their artists lose on some earthy stuff. It's just such a pity that Fontella & Bobby didn't record more than just their few Chess/Checker sides.
For the record: Checker # 1097 was released towards the end of '64 or in early Jan. '65. The A-side made it to r&b #5 (BB) at the beginning of March and hit #29 on the Cashbox Top 100 in early April.
Fontella Bass & Bobby McClure: »Baby What You Want Me To Do« on Checker # 1097 (1965):
Postscript July 7th 2012: Read more about Fontella Bass here.