Just smoke and enjoy, dont worry about other peoples opinion. Im a youth pastor and I founded the pipe club in town, which many would think as odd, but in the context of God's word it isnt a sin to smoke or drink for that matter, I see it as a fine gift from God, and it is a way for me to meet people and share the gospel. Try that next time, change the subject all together and ask them about Jesus. If they ask about smoking being a sin just tell them that smoking isnt a sin, but addiction is. The Bible says not to be mastered by anything, addictions compete with the true Master, but the pipe can be enjoyed in praise to the Master and could be a great tool to tell others about him.