there's no rule that says you should not run to the bathroom after TTC. honestly, it's only a theory that sperm may have to work against gravity. What we do know is, sperm know where they are going and instantly start swimming to get into the cervix / tubes. I think lying down, having your hips elevated, standing on your head, is just a way to give a person peace of mind that the sperm are going in and not out.
I'm sure there will be stories from women who swear that them standing on their head was the reason they got a BFP...but you also have to remember there are countless women who fall PG without even trying and i doubt they were standing on their heads after their bd session!
If you need to use the bathroom after you BD to avoid a UTI, by all means, do it! I would not risk it, to be honest. If you think you can hold it for 5 min or more, that is your choosing and it's fine. Either way i think you will get a BFP in the end! Good luck!
