Verb. When a girl is sucking on your balls and the shaft of your penis looks like a snorkel running parallel to the side of her face. If the girl is wearing glasses, it adds to the effect by mimicking goggles. Hence "Portland", because all the hot girls wear glasses.
Ed told me he got a Portland Snorkel for Sarah last night in the library. What a whore.
Giving a snorkel(sucking ones balls while jerking the cock so it looks like a snorkel)in the shower.
I was taking a shower last night and your girlfriend snuck in to give me a Portland Snorkel and I nutted all over your shampoo bottle, sorry.