Keenan Allen Aims Crotch Grab at Seahawks Fans After Chargers Victory

Keenan Allen's got a little bit of Marshawn Lynch in him -- 'cause after the Chargers WR lit up the Seahawks on Sunday, he busted a crotch grab aimed right at some Seattle fans!

TMZ Sports has the footage showing Allen walking toward the tunnel after L.A.'s 25-17 victory over Seattle ... and grabbing his junk while staring at some loud Hawks fans at CenturyLink Field in Seattle.

After two solid pumps -- Allen playfully stuck out his tongue at the fans and continued into the locker room.

Allen had a helluva game -- hauling in 6 catches for 124 yards and 2 rushes for 28 yards. He was in a good mood.

Guessing Allen will likely get fined for the gesture. Also guessing he knew that already and didn't care because he's in the middle of a 4-year deal worth up to $49 million (with $20 mil guaranteed).

For comparison, Rams star Marcus Peters was fined $13,000 for busting a crotch grab while diving into the end zone earlier this season (in a tribute to his pal, Marshawn Lynch).