We fell pg the month that I thought we wouldn't - DH had been out field for 2 weeks, and I was sure he'd missed my O time. So we really relaxed...gave each other a massage, then just enjoyed ourselves. Afterwards, I put a pillow under my bum and lay with my legs in the air (out of habit from TTC more than anything), and 2 weeks later we got our BFP.
Also, DH had been taking zinc supplements, which build up the amount of semen - even he noticed the difference in the quantity! Sorry if TMI.
Good luck to all the TTCers...we'll be joining on that journey soon enough!