From 1d4chan
Sometimes they model their bikes after their favorite wolves so they can yiff without actually yiffing.

Swiftclaws are yet another Space Wolves exclusive unit. They are the equivalents of the Dark Angels Ravenwing, however unlike most Space Marine riders, who use their bikes for reconnaissance, the Swiftclaws' main roles are demolitions and close assault operations. Blood Claws are by nature eager for battle, and many are so intoxicated with the power and speed of a Space Marine Bike that they demand permanent assignment to a Swiftclaw Pack. Swiftclaws are sometimes assigned to a dangerous mission that demands speed and daring, such as navigating a treacherous stretch of land in pursuit of a hated enemy, or to rescue a lost chapter relic ahead of a closing enemy force.

Given the opportunity to sow the maximum amount of carnage and disruption possible, these young warriors apply themselves with particular relish in the performance of their duties.

With their enhanced senses, and their survival experience (standard for any native of Fenris), Swiftclaws can spend months on a long-range hunting mission, without needing resupply. On such missions they are often accompanied by Fenrisian Wolves so they won't go too lonely without their fellow Yiff companions. When the time comes for them to strike, Swiftclaws have only one rule: that their objective be achieved with as much fanfare as possible. To this end, Swiftclaws can be equipped with melta bombs, krak grenades, and bolt pistols. One of their favored tactics is to set fire to their enemy's stronghold, then ride straight to the center, boltguns blazing.

Forces of the Space Wolves
Command: Wolf Lord - Wolf Guard
Priesthood: Iron Priest - Rune Priest - Wolf Priest
Troops: Blood Claw - Fenrisian Wolf - Long Fang - Skyclaw
Swiftclaw - Thunderwolf Cavalry - Wulfen - Grey Hunter
Walkers: Dreadnought - Space Wolves Dreadnought
Wulfen Dreadnought
Vehicles: Bike Squad - Rhino - Razorback
Land Speeder - Predator - Vindicator
Whirlwind - Land Raider (Land Raider Crusader
Land Raider Redeemer - Wrath of Mjalnar)
Special Vehicles: Stormrider
Flyers: Stormfang - Stormwolf
Spacecraft: Boarding Torpedo - Drop Pod
Space Marine Landing Craft
Allies: Space Marines - Primaris Marines