No someone can't a STD from someone who does not have it.
You won't catch STD's from smoking after someone with a STD.
It would not be likely to catch a STD this way, unless the finger had an infected fluid on it (such as sperm or blood).
Technically I dont think so but remember that Herpes (cold sores) are a form of an STD
Here's a site with more info on STDs... http://linkisking.com/jk.cgi?i=D8dRZeY&d=www.epigee.org%2Fguide%2Fstds.html%20&n=15 copy and paste the link No they have to have the STD in order to...