Get 40% Off All Pizzas At Papa John’s With the PapaSlam Promo Deal! April 20, 2016 by Couponer Post contains sponsored/affiliate links and I get commissions for purchases made from links. Celebrate baseball season with this new deal at Papa John’s! Anytime a player hits a Grand Slam you can get 40% off the next day with the promo code, PAPASLAM! Watch baseball and save at Papa John’s!