Whilst I haven't had my next round of treatment yet my doctor advised me when she told me I had to have a cone biopsy that I would not be able to have sex or insert anything into the vagina for 6 weeks. I have seen on numerous websites they reccomment 4-6weeks depending on if you are still experiencing discharge. This is to prevent infection and promote healing of the cervix.
My friend had Lletz about 6 weeks ago and had sex for the first time and said she experienced some spotting afterwards. However, she smokes so perhaps the wound is taking longer to heal. I have held out for the 2 weeks after my biopsy just to be certain I do not get an infection, I feel like that is the last thing anyone needs to go through after all the treatment trauma!
Hope it helps a little :)