This term was built out of the words samisfied/samisfaction and Sam. Sam is regarding to other definition a great guy who knows what's up and how to treat a girl.
The term samisfied will be used, if Sam has successful sex with a hot girl (at least a 9 on the scale to 10). It can only be used if the girl really enjoyed the act.
Samisfied can also be used as a pick up line. Check the example.
Two girls talking...
X: How was your night yeasterday with Sam
Y: Oh damn I got samisfied
As a pick up line...
: Girls are you ready for some samisfaction.