The duo's debut was released in the summer of 2018, unveiling a world that was tangibly different to their work apart, sonically "so vivid and sort of psychedelic," Marling says, "and the lyrics so un-thought through".
As with the first album, Marling would arrive in the studio without having heard any of Lindsay's music, with the hope that it would bring the lyrics an immediacy and a spontaneity.
Having become interested in psychoanalysis, she found she drew heavily on her psychoanalytic texts for this album"s lyrics.
"I was taking the train down and I had prepped by putting a glossary of words in the back of my notebook," she says.
"Ordinary words that are used differently within psychoanalysis, like 'object' and 'master'; I felt I needed something to base the lyrics off.
"I like the idea that psychoanalysis attempts to investigate the routes of desire."
There were other sources too: half-memories, family stories, strange dreams; things she had read, or been told or imagined.
"LUMP is so the repository for so many things that I've had in my mind and just don"t fit anywhere in that way," Marling says.
"They don't have to totally make narrative sense, but weirdly they end up making narrative sense in some way."
It was trickier second time around. Both felt the pressure to create an album as instinctive and magical as the first.
For Marling there were other challenges too. Having moved to a coastal town, Lindsay had been inspired to begin writing music somewhat inspired by the sea now on his doorstep.
"Waves go in circles of seven, so I started to write all the music in seven form," he explains.
"But the thing is pulling out the rhyming pattern in the tracks that were written in 7/4 was very difficult for my brain to get my head around," says Marling.
Simultaneously, Marling was working on her widely acclaimed, Mercury Prize and Grammy Award nominated album Song For Our Daughter, and working on LUMP material felt liberating and distinct.
"It became a very different thing about escaping a persona that has become a burden to me in some way," she says.
"It was like putting on a superhero costume."
"Even now," she says, she sometimes feels as if she might be "edging Laura Marling off a cliff as much as I can and putting LUMP in the centre."
Sometimes she would disappear to the kitchen, pace around the garden, or sprawl over the sofa as she wrestled with a chorus, a verse, a time signature.
Beneath his headphones, Lindsay did not press her. He waited, confident that soon enough she would find the words.
Not even when the lyrics came did he ask for their sense or explanation.
"I don't ask, I don't ask, no," he says.
"I just form visions. I can see these scenarios and I"m imagining situations, but I also feel they"re symbolic."
Animal was a word Marling threw into a lyric simply to meet a rhythm. But it seemed to capture the mood of the record, and of the band as a whole.
"There's a little bit of a theme of hedonism on the album, of desires running wild," she says.
"And also it fed into the idea we had from the start of thinking of LUMP as a kind of representation of instincts, and the world turned upside down."
It is something childlike and grotesque and filled with possibility, they say.
"We created LUMP as a sort of persona and an idea and a creature," says Lindsay.
"Through LUMP we find our inner animal, and through that animal we travel into a parallel universe."
LUMP will take 'Animal' (released on 30th July) on tour, with a date at Patterns, Brighton, on 5th September 2021. Tickets for the headline show are on sale via www.lump.world.