Question on sperm life and mobility outside of body

[semfunbat]

I had a few questions about the lifespan of sperm and whether it can travel (be mobile/swim) outside of vagina and still be live -

How long can the sperms live in an ejaculate in an underwear? I had a wetdream. I only changed underwear after about 4 hours (i know the time because I checked time when I was briefly awake after wet dream and then slept back). When I changed underwear (took shower) I did see couple wet spots on the underwear, rest was dry. Does that mean there could have been live sperms in the underwear? I thought in 4 hours they should have all died.

I am asking the above because when I removed underwear, and it hit carpet, is there a chance of live sperm transferring from either my skin or underwear to the carpet/floor area in bathroom? My partner also changed clothes right after I did and had her underwear around the same spot where I changed. Therefore my next question. Is there a way sperm can transfer from floor/carpet to underwear? I mean can sperm move like that (similar to spilled drops of liquid transferring from floor to clothes)?

[Heather]

We won't engage with pregnancy scares as our policy.

That said, none of this is how human reproduction works -- for example, sperm cells can't move on their own in any circumstance -- and it sounds like you simply may not know how it does. Here's a piece that can give you that education clearly and in one fell swoop: Human Reproduction: A Seafarer's Guide.