Discreet public breastfeeding is learned skill, just like breastfeeding itself. Practice at home in front of a mirror first, and you'll soon see much less skin (okay, boob) than you feared.
Experiment with different kinds of clothing to see what works best for you. Some moms like to wear looser tops that lift up from the bottom; others prefer button-up shirts or those with slits or flaps made especially for nursing. Nursing tanks or camisoles keep your stomach (and those stretch marks) covered while still allowing baby access to your breast. You can also drape a receiving blanket or shawl over your shoulder and baby's head as he slurps away. Another strategy: Wear your baby in a sling to hide what's happening and keep your hands free.
watch: public breastfeeding tips from real moms