I agree with severin76. Altough penetration is not necessary in order to get pregnant, conditions must be favorable for sperm to swim. In this case, they were not.
In my opinion you do not have to worry because the chances of getting pregnant under the circumstances which you described are close to zero.
Penetration is not necessary in order to become pregnant. So, there is a slim, marginal risk of pregnancy with the sexual activity that you described.
Yes, there is a risk of pregnancy. Anythime sperm comes in contact with a womans vaginia, there is a risk of the woman getting pregnant.
I think the Penis and or sperm need to actually penetrate the vagina for you to be concerned about any of that. they may be good swimmers but there not too directionally equipted. yea they can soak through your clothes but I doubt they will know to over come the other obstacles of gettin up in there :)