We've had some bad experiences with TPR and TPE toys touching other toys over the years. Usually silicone will win the battle if it's touching TPR/TPE, but might come out color stained. As for silicone on silicone, it depends on *whose* silicone. We've tossed Tantus toys together many times without any problems. However, we had 2 "silicone" toys from Cal. Exotics stick together before.