Patka is a Sikh head covering which is worn by many Sikh children in preference to its bigger brother the
turban. The Patka is also worn by many adult Sikhs as a under-turban as well, just as we use other underwear of different colours. This under-turban may be kept at bed-time as well, when the turban proper is taken off. similarly, during swimming and sports, the turban is replaced by a small scarf-sized cloth called the 'PATKA'. This is knotted at the top to keep the hair intact.
Reference:: Sikh Philosophy Network http://www.sikhphilosophy.net/sikh-youth/17633-how-to-tie-a-patka.html
In fact PATKA is more popular with young Sikhs at school. The patka is a simple cloth head covering, consisting of about two square feet of fabric with strings to secure it. The patka is usually worn by Sikh youths, or in the place of a turban by less traditional adult Sikhs.
this is intended for other white males NOT in a sikh family.. I found this vid VERY helpful: