It can be done on the day of punyahavachanam
Method is not given in written perfectly, it is only in practice, so, I can't explain it.

Dear you, Thanks for Visiting Brahmins Net!
JaiHind! Feel free to post whatever you think useful, legal or humer! Click here to Invite Friends

Seemantham can be done even the girl is in bed,
mookupizhidal, vahidu eduththal can be done at bed.