Some training types work after spamming it 10-20 times, but the penetration lessons haven't worked for me at all after C.
A couple more bugs, selecting the deprivation suit punishment does not display an image properly. Selecting perverse games > fisting during active sex soft-locks the game.
The deprivation suit images will be corrected tomorrow.
Meanwhile, the master-ia and media-base-ia branches are updated with a fix for the active sex soft-lock and a rebalance of the sex skill leveling rate. You'll want the media update because it includes new purple energy stars without which your slaves may appear to have no energy at all when they have reached their daily exercise limit (a new balance mechanic in 2.2 that says the number of times you can safely exercise each day depends on the slave's endurance level).
Also, inspired by
earlier comments on the thread, intellect and temperament are now important stats for sex skill training; a slave with S+ intellect and temperament will have enough of a bonus to reduce the number of lessons required for level-up to B+ and higher levels compared to an otherwise identical slave with B+ intellect and temperament.
With three exceptions, all skills required for the concubine specialization can be leveled to B+ or below in a single lesson if you have sufficient bonuses,
even with an unskilled slaver character, for slaves with at least B+ intellect and temperament. There are 23 skills in the skill categories required for the concubine specialization, and several of them are linked so that they increase when other skills are trained. According to my calculations, it should be possible to train a B+ concubine within two decades (measured from the time when you achieve sufficient obedience to begin sex training). Note this assumes that if you have an unskilled slaver you will use item bonuses to compensate for that; otherwise, training to B+ will take around twice as long. Having S+ intellect and temperament can allow you to level up most of the skills to B+ in a single lesson with less than the
maximum item bonus, but still requires a moderate bonus from items or master skill.
Beyond B+, eleven of the thirty-four sex skills can be raised to A+ in a single lesson, the others require a minimum of two lessons (or three in a couple of cases). To reach S+ requires a
minimum of 2-3 lessons depending on the skill. These are
minimums, it can take twice that many lessons, or more, depending on all the relevant factors.
In general, master skill is treated as interchangeable with item bonuses for sex skill leveling; if the master has A+ skill, that's equivalent to having boots, a corset and a nipple chain. An exception is made when leveling skills to S+; for that, having item bonuses
plus master skill can reduce training time, so those items remain useful in the end-game.