Hello amit, it means that without any gap, for example if you give exam in 2019 and also in 2020 this means that you appeared for jee exam consecutively in all attempts.

I hope this helps, all the best.

Hello aspirant, 

Jee main is conducted twice an year.Two consecutive year means 4 consecutive  jee main exams in 2 years. For example you can write jee main 2019 twice and you can repeat it in 2020.Totally one can write jee main exam 4 times in two consecutive years.