An expression, announced when, during a conversation, the speaker accidentally spits or sprays saliva in the listener's face. Either speaker or listener will say 'spibib' in order to acknowledge the occurrence, and to remove potential embarrassment from either party, before the spit is wiped off face.
Similar to gesundheit, 'spibib' is intended to provoke a joyful reaction to counter social embarrassment. It's formed of 'spit' and 'bib', in a situation where the bib is the listener's face.
Dave: "Hi Laura." (Laura is hugely attractive)
Laura: "Hi Dave."
Dave: "Do you want to go see Tree of Life tomorrow? It looks SENS((accidentally sprays saliva in Laura's face))ATIONAL" (Dave realises he just spat in Laura's face.. shiiiiiit)
Dave: Hahaha. ("Laura is lovely, and realises I didn't mean to spit in her face... phew... I love her".) Sorry!
Laura: Hahaha. It happens to the best of us. Let's totally go to the film!
Jo: "So I was talking to Mike's mom the other day, and she was getting really into memories of him as a kid and then she totally spibibbed on me!"
Rachel: "Oh no!"
Jo: "It's fine. I just said spibib, and she laughed, so it's all cool. Mike's mom is awesome".