In regards to "decency", who can really make a valid assessment? It is only God and He is holy. By society's standards, decency is a subjective spec on a wide spectrum. For some, the definition of decency may be too conservative. For others, it could be too liberal. How can we best estimate what is considered decent? It is not that the church is against all kinds of dancing because we are obsessively rigid. We must exercise caution because it is the understanding of the Church that the body is considered a temple of God. It is consecrated to God from the day you were baptized. Therefore, you have an obligation to keep it pure for in which God will dwell. The apostle Paul asks us these poignant questions, "Do you not know that your bodies are members of Christ? Shall I then take the members of Christ and make them members of a harlot? Certainly not! Or do you not know that he who is joined to a harlot is one body with her? For 'the two,' He says, 'shall become one flesh.' But he who is joined to the Lord is one spirit with Him" (1 Corinthians 6:15-17).
Dancing is mentioned many times in the Holy Scripture with a positive connotation, but it is also mentioned with extreme danger in other situations. Dance in a pure form and intention, as it is mentioned in the Holy Scripture, is a gesture of joy according to God's conquest and deliverance of His people from hardships. However, the Holy Scriptures directs us to understand that dance can also be harmful and provocative and result in causing others to sin. The seductive dance of Herodias caused Herod to succumb to her evil plot of killing St. John the Baptist (Matthew 14:3-12; Mark 6:14-29; Luke 9:7-9).
The dances at various occasions which today's society has become all too accustomed is more inclined to be the worst form of amusement used to celebrate a holy sacrament. Think about how you feel after you have taken the Holy Eucharist. How do you feel after you have poured your heart out to your Confession Father, and humbly stand or bow before him as he finally places his hand upon your head and you close your eyes while meditating on the powerful words of the absolution, then open your eyes and see the sleeve of his black robe as he holds the cross above your head and blows your bondage away? Think about the infant or the adult who after Holy Baptism and Holy Chrismation desires to rest and has the best day and most peaceful night sleep ever. Think about receiving the Unction of the Sick and feeling secure that whatever happens, it is God's will and you are in His grace. Think about attending the ordination of a priest and the awe-inspiring messages and blessings he receives in order that he may consecrate his entire life to serving God and His people. How then can the sacrament of Holy Matrimony be any less reverent? Holy Matrimony was the first sacrament mentioned when God created Eve and then brought her to Adam (Genesis 2:24). Holy Matrimony was also when the first miracle was performed by our Lord Jesus Christ, and just as the Holy Trinity attended the first marriage (Adam and Eve), the first miracle occurred while Christ attended a Holy Matrimony (John 2:1-12).
Therefore, ask yourself if this dancing that you have in mind can cause your brother/sister to stumble. The question is not only will it, but can it, meaning does it have the potential of causing one to stumble (Mark 9:42)? Do you want to take personal responsibility for this result? Also, ask yourself if these activities will edify your guests? "All things are lawful for me, but not all things are helpful; all things are lawful for me, but not all things edify" (1 Corinthians 10:23). Keep in mind that there are many various guests at celebrations and each one is at a different stage of spiritual development. "Therefore comfort each other and edify one another, just as you also are doing" (1 Thessalonians 5:11).
