The phrase "to make a rub" means to create a mixture of spices and herbs that is applied to meat or vegetables before cooking to add flavor. Full definition
Make rub for chicken: Pulse basil, garlic, oil, salt, and pepper in a food processor until roughly chopped. (myrecipes.com)
The tan boot fit just fine, but strangely, the black pair was too tight in the toe box and also not long enough, which made it rub at the heel. (gearbuyer.com)
Make the rub by mixing all the ingredients together with a pinch of salt. (bbcgoodfood.com)