The phrase "extremely comfortable with" is correct and usable in written English.
It is used to describe a level of comfort or ease with a particular situation or idea. For example, "I am extremely comfortable with the changes that have been made to the project".
We are extremely comfortable with our process for monitoring the ratings of municipal securities".
Downstairs there are 421 seats, extremely comfortable, with capacious legroom and (intermittent) armrest tables.
"All 11 players are extremely comfortable with the ball," midfielder Aly Wagner says.
Thomas said he did not need a public vote of confidence, saying, "I'm extremely comfortable with where we are".
"He is the top of the ticket, and I joined it knowing this and being extremely comfortable with it".
The only important thing is that I am the one who was hired, and I feel extremely comfortable with both the school board and community.
An extremely comfortable palazzo with garden and parking lot.
Poshness is, by its very nature, relative, and toff-bashing is frequently the preserve of people who have led extremely comfortable lives, with middle-class parents who propel them up the property ladder.
The first thing almost everybody who knows Obama says about him is how extremely comfortable he is with himself.
Wearing shorts and carrying a new, extremely comfortable backpack loaded with water, various energy bars, a pack lunch and a fleece jacket to wear on the summit, I had become a hiker.
Extremely comfortable overnight sleepers – with cinema and a very lively bar car – depart Stockholm each evening and call at Arlanda international airport before arriving in Are at 7.30am the next day, just as the ski lifts start to swing into action (skistar.com; visitstockholm.com; sj.se).se
