Dude...they put directions on the condoms for a reason. Read them.
The tension of the condom against your wang is what keeps the seal. If you go limp-**** while in one, cvm can leak out around the edges.
Dude, they're like $3 for a three-pack around here...they're in the grocery store a foot away from the toothbrushes. And they even have self-checkouts if you're embarassed to hand them to the cute girl working the register.
Is there anywhere, aside from those dispensers in sleazy bathrooms, where you even CAN buy condoms one-at-a-time any more??