The cum idea is easily the best. Cum in the bottle for a few days, then put a note telling just that on it. Or perhaps something a bit more subtle if you like, "cumbucket!" or something like that. The best thing, you can always get away by acting a victim if you can't handle his reaction :>
The sodium hydroxide/caustic soda (same thing) idea is not just gonna hurt. In best case he'll get away with severe chemical burns, in worst case he'll end up blind. Don't even consider doing that.
The sodium hydroxide/caustic soda (same thing) idea is not just gonna hurt. In best case he'll get away with severe chemical burns, in worst case he'll end up blind. Don't even consider doing that.