Making use of Claws of the Umber Hulk

[TheRedTemplar]

The Claws of the Umber Hulk (a module-exclusive item to the Princes of the Apocalypse campaign) is an extremely unique magical item in many different ways. It always comes in pairs (i.e., one for each arm), both act as Magical Longswords (they do 1d8 slashing and use Strength, and they're a magic item), and they keep you from using certain objects and somatic spells. However, they have two interesting traits that separate them from most magic items:

The first one is that, regardless of class or weapon proficiency, you always have proficiency with the Claws as long as you're attuned to them. This means that every class from Fighter to Wizard can use these bad boys to tear enemies to ribbons.

The second one is the power to burrow; that is, the Claws give you the burrowing speed of an Umber Hulk (20 ft.) and the power to tunnel through solid rock at a rate of 1 foot per round. As far as I'm aware, they are the only way in 5e to gain a Burrowing Speed without Polymorphing into a monster or animal that has one. And burrowing is a pretty nifty thing, since it lets you tunnel under the earth.

My TWF Fighter got these, and I want to make sure they don't go to waste. What would be a good way to use the Claws and their burrowing speed? I imagine shenanigans like grabbing the Duel-Wielding and Mobile feats (both of which I already have), punching people, then tunneling underneath them so they can't retaliate. Could anyone help me make use of these?

[Vanguardian]

A fighter who stays of reach of his enemies is a good way to have the party killed (unless you are the squishiest member by a wide margin).
Use the claws to travel past obstacles, to make ambushes (since you seem to be Str focused, your stealth is probably not that high) and to disengage once you find yourself near dead and with your second wind already used.

[TheRedTemplar]

A fighter who stays of reach of his enemies is a good way to have the party killed (unless you are the squishiest member by a wide margin).

Well I mean, I wouldn't do it all the time. I'm not the party tank though, I'm more for DPS and diplomacy (Purple Dragon Knight). I was mostly referring to if I'm starting to get hurt too badly or the enemy is a spellcaster/dragon/etc, or has some special attack that uses saves, so I could just tunnel bellow to avoid it. I'm squishier than most fighters, and we only have one caster in the group anyways.