As Tanquerey says in La Vie Spirituelle:
We cannot attain to union with God without mortification, without detaching ourselves from the inordinate love of creatures.
The aim therefore in mortification is to think upon its End (union with God). We must not be too attached to it for its own sake as this defeats the object. We must not think for a moment we can achieve results by ourselves (Pelagianism), everything must be prayerful or atleast detached from any notion of a merit attached to the mortification. We must be lighthearted and joyful, God delights in his people. Letting His grace work in us cannot be achieved if our hearts are like stone, we must have some measure of holy delight as God delights in us.
All this was brought home to me when I was in Soho earlier this week [a district of London famous for its loose moral code, gay bars and secretive but tangible Chinese underworld]. I was only there for the fabric shops and the food, innocent enough pleasures but for yours truly whose senses are more accustomed to the bucolic delights of rural Wessex, it was a bit of a shock.
So what, practically, can a Catholic do in 2013 to mortify the body and the senses? Here are some possible suggestions, in no particular order and of no particular significance, it is what you do with your heart that is important.
When you are gobsmacked and even allured by the allusions to the sins of the flesh that assail your senses:
recite the opening lines of Psalm 64:
A hymn, O God, becometh thee in Sion: a vow shall be paid to thee in Jerusalem. O hear my prayer; all flesh shall come to thee.
Or Psalm 67
Let God arise and let His enemies be scattered. Let them that hate Him flee from before His face.
If a sense of moral/intellectual superiority starts to well up inside of you because you are a Catholic:
Use the public toilets and leave them in a better state than before you went in.
Never break the speed limits when driving.
Always give way to buses and white vans when driving.
Smile at strangers.
Ask yourself how many people have come to the Faith through your example.
On social media
If you are going to write anything on Twitter, write it as a Haiku.
Avoid the blog that calls itself Rorate Coeli
Never spread gossip
On dress and deportment;
Walk slowly and carry yourself well (no slouching, no swagger, no slinking)
Dress modestly and dress well but avoid expense.
Avoid fragrances that will invade another's personal space.
Do not use any electronic device whilst walking.
On custody of the eyes.
Keeping your eyes averted is not possible or indeed safe with the traffic as it is, so discipline yourself to look caringly at others with disinterest (this is not a contradiction, you can only really care if you are not bound up with self-interest).
Pray for anyone whose appearance or actions deliberately or unknowingly arouse sexual thoughts in you. Pray that their guardian angel will protect them from the hurts caused by the thoughts of others and pray that their minds may be turned towards healthy self-respect.
If you catch a stranger's eye and the exchange penetrates deeper than expected, pray that your eyes reflect Christ (in all modesty, goodness and innocence) and not you.
Don't. Find something to do.