The term Vakra refers to ‘crooked’; referring to a scale or pattern that follows a curved, zigzag pattern. The swaras that makes up these varisais may go up and down- for example 2 steps forward one step back or include a janta pattern along with a note with elongation lke SS R S,R. Here SS is jantai pattern which have twin swaras and S,R is a swara phrase with Karvai or elongation. The swaras are not in regular/sequential ascending or descending pattern.
The lyrics for these Vakra Janta Varisai have already been uploaded here. https://anuradhamahesh.files.wordpress.com/2010/09/02-vakra-janta-varisai.pdf
Read here to know Why students should sing Varisais – https://anuradhamahesh.files.wordpress.com/2010/09/02-practical-exercises-why-should-you-sing-varishais.pdf