Hi,
I'm and MD and am TTC conceive with my wife. I did a literature search on Preseed as there seems to be a lot of questions about it and found this article:
J Assist Reprod Genet (2014) 31:333339
The effects of vaginal lubricants on sperm function:
an in vitro analysis
(this website won't actually let me post the article or links but if you go to pubmed dot gov then you can search the article to read it yourself.)
This article compares different lubricants and their effect on sperm viability, fragmentation and mobility invitro. They concluded that Preseed out of the 9 lubricants tested had the best overall viability and motility without any sperm DNA framgentation. Even though this was laboratory tested and not live tested, I plan on trying this with my wife as she often has slight amount of CM during her time of ovulation and this may help with lubrication as well as motility/viability as that is what CM is supposed to aid in. I feel it is at least worth a shot.
Hope this helps anyone TTC. Good luck. For the record I have no affiliation with Preseed.