The "Customers who bought this also bought" feature - can we "rig it"

[Fuzzbutt.co.uk]

Just wondered if there was a contribution or any way you can specify what is displayed in this section, so when we stock new gear we can in effect, plug it to customers by linking it with other bought products? I know that it happenes automatically thru orders placed, but I want to make my slow-selling products appear in the "also bought" section to help sales. Is this possible?

[burt]

There are a couple of contributions which do something like this, but I can't remember which ones. "Related products" rings a bell?