I started adding in a few sets of forearm exercises after bis with a wrist roller. Just a steel pipe with a string and a weight that you roll up while holding your arms straight out. Roll the weight up and down until failure for about three sets or so. My forearms feel like they are about to burst when doing this on cycle.. After a few weeks, my bicep and back exercises weren't really working my forearms enough to get the kind of pump that made it difficult to hold onto anything. My barbell shrugs even jumped a bit in weight from the stronger grip as well.. up to 475lb now on tren/prop.
You might want to give it a try.. it probably can't hurt, but I would save it for the end, as it's difficult to load plates onto anything after doing this, let alone trying to hold onto anything.