I got you bro:
Basically, during levels 1-3 the only thing that matters is filling the massage satisfaction (

) bar, but on level 4 you need to make Dana feel both satisfied and embarrassed (blush icon bar) and levels 5-6 require Dana to be both embarrassed and aroused (heart icon bar) in order to progress. You need to be at dominance level 7 before the end of week 10 in order to get the true ending.
Problem is, the embarrassment (shame) bar doesn't increase while Dana is asleep, so you need to keep her awake as much as possible. This is easier to do on later levels, as you will be able to sexually harass her more without pissing her off, and she doesn't fall asleep when the certainty [!] bar is active, but level 4 is kind of tricky.
Easiest way is to beat level 4 is to start the massage with a full 90 minute timer and no bra on Dana. You can achieve this by massaging all fatigued (red and yellow) body parts to 0% fatigue while at dominance level 3.
Spam erotic lv 2 spots until Dana falls asleep, then use the tongue or dick until she wakes up. When she starts getting angry and the [?] bar becomes [!], massage a lv1 spot until she falls asleep, then use dick or tongue until she wakes back up. Repeat from the beginning and you should be at level 5 next week.
Some other tips fyi:
Generally, you should avoid picking the green body parts until level 4, which is the earliest Dana will take off her panties and let you smash, although if this is your first playthrough I recommend waiting until level 6-7 where it is much easier to do her.
Starting at dominance level 3, Dana will take off her bra if you ask nicely, and at level 4 she will take off her panties. At level 5 you can order her to remove her bra, and at level 6 with her panties. You can use these commands at lower levels to easily embarrass Dana, but she may slap you, and after 10 slaps the game ends regardless of dominance level.
Dana's goon count starts at 2648 and increases depending on how embarrassed she gets during each massage, with the maximum being 40 times per week. Although if you raise the shame bar at all during level 1 it will glitch the number, resulting in it being only 600 something (lol).
The forbidden massage technique, where you insert the dick into any body part while Dana is asleep, and then pull out as soon as she wakes up, will actually lower the [!] and [?] bars instead of raising them. This is probably a bug but it works great when combined with the tongue.
This game is buggy as hell, and some erotic lv 1 and 2 massage spots actually register as lv 3, which could result in Dana getting angry, slapping you, or even triggering the bad ending. Stick with one spot that works for you if you're having trouble clearing early levels.
The ass body part has no erotic lv2 massage spots, just 1 and 3. The legs only have lv 1 spots, so do them early rather than later if you're trying to increase the shame bar. Also slotting the ass body part into both the 30 and 15 minute (final two) segments results in Dana and massage table disappearing with no way to continue, so pick two different body parts (ass can still be one) to avoid having to restart the game.