Yes dear you can opt for spot counselling if you have not participated in anyone of the round.Firstly you would have to register for spot round counselling. The registration form would be available if seats remain vacant after normal counselling. After this, they will publish a list of registered student ranked in order of their marks. After this everything would be the same as normal counselling process.Also you will have to pay fee while registering for spot counselling which will be adjusted in course fee.

Hope this helps.