Use of "づ"
"長く甘い口づけを交わす"
I extracted this from a Japanese song. Here's the question, why is "づ" used instead of "ず" in this case?
I don't think we will be seeing "づ" very often in normal Japanese?

Question

Use of "づ"
"長く甘い口づけを交わす"
I extracted this from a Japanese song. Here's the question, why is "づ" used instead of "ず" in this case? 
I don't think we will be seeing "づ" very often in normal Japanese?

Answer

口づけ　…　　口をつける  を略した表現　

　　
口ずけ　…　　口をすける　　→　意味のない言葉になる

so in this case, we can only use つ.