Eastern Orthodox/making the sign of the cross
When the Trinity is mentioned, we of course make the sign of the cross. Why do we make it when the Theotokos is mentioned?
When we make the sign of the Cross varies a bit from one congregation to another. I know of no "rule" regarding making the sign of the Cross when the Theotokos is mentioned, but neither do I see why it would be inappropriate.
Christians have been using this gesture since the earliest days of the Church. It has changed a bit over the centuries, but has never lost its basic character.
1# Bring together the thumb, forefinger, and middle finger of your right hand to make a peak. This represents the Holy Trinity.
2# Fold your ring finger and pinkie into your palm. Let this remind you of the Son incarnate, come to earth as God and man.
3) When the Trinity is mentioned, touch your three peaked fingers to your forehead, belly, right shoulder, and left shoulder, thus tracing a cross in your body.
4) Drop your right arm to your side, and relax your hand.
5) Bow toward the Altar.
It's almost easier to list when we do not cross ourselves, the prime example being when we are near the Chalice, lest we cause a spill. That's why we cross our arms over our breast, pinning the right arm with the left to prevent what becomes an instinctive movement.
We cross ourselves when we enter and leave the temple.
We cross ourselves when we cross the center line of the temple, i.e. when we walk in front of the Altar Table.
We cross ourselves at the beginning and end of the readings of the Apostle #Acts/Epistles# and of the Gospel.
We cross ourselves when we recite the Creed, at the mention of the Father, the Son, the Holy Spirit, and the Church.
We cross ourselves when we recite the Lord's Prayer, the "Our Father."
We cross ourselves when we venerate an icon, twice before we kiss it and once after.
We cross ourselves when we hear the Trinity mentioned. But if the doxology is split #Glory to the Father... prayer... both now and ever...# we only cross ourselves at the "Glory..."
There is some variation on what to do when the Priest or Bishop blesses us. I don't cross myself then. It seems a bit redundant to do so.
After a while the gesture becomes so natural that we cross ourselves whenever we hear a dog bark or someone drops a fork.
The sign of the Cross reminds us to take up our own cross daily. It reminds us of the price Christ paid to save us. It reminds us that we may be called to be martyrs for the Gospel. And it is a powerful symbol which the demons fear and despise.