This was fun. Slormgorm frequently coincides with my blogging slot, and every time I start off thinking that the familiarity developed from past blogs will help in solving each new puzzle. Wrong again, since this puzzle provided its own twists and turns.
I am not sure that I have ever seen TUMEFIED in real life, but it was deducible from the clue.

| ACROSS | ||
| 1 | TUBBIEST |
Most well-upholstered bath cap that one wears (8)
|
| TUB (bath) + {I (one) inside (that . . . wears) BEST (cap)}, with a euphemistic definition | ||
| 5 | OTHERS |
Parents in need of bit of mollifying rest (6)
|
| [M]OTHERS (parents) minus (in need of) first letter of (bit of) M[OLLIFYING] | ||
| 10 | MALACHI |
Prophet from a church in African state (7)
|
| {A + CH (church)} inside (in) MALI (African state) | ||
| 11 | AFFRONT |
Deliberately offensive act in a show on radio (7)
|
| Homophone of (on radio) A FRONT (a show) | ||
| 12 | FLYWEIGHT |
One boxes whey gift up with muscleman essentially (9)
|
| Anagram of (up) {WHEY + GIFT + middle letter of (essentially) [MUSC]L[EMAN]} | ||
| 13 | SOBER |
Plain and dull as all teetotallers are? (5)
|
| Double definition | ||
| 15 | EXAMS |
Chopper to be reviewed by Sunday after mass tests (5)
|
| AXE (chopper) reversed (to be reviewed) + M (mass) + S (Sunday), with “after” indicating the order of the wordplay | ||
| 16 | GENITALS |
Privates stealing explosive (8)
|
| Anagram of (explosive) STEALING | ||
| 19 | ACIDHEAD |
Tripper did ache badly after accident at front (8)
|
| First letter of (at front) A[CCIDENT] + anagram of (badly) {DID ACHE} | ||
| 20 | IBIZA |
Business located in Iowa holiday spot (5)
|
| BIZ ([slang for] business) inside (located in) IA (Iowa) | ||
| 21 | CARDS |
Knaves smuggling rupees for knaves? (5)
|
| CADS (knaves) around (smuggling) R (rupees) | ||
| 23 | LAVENDERS |
Reason old queen enters loos to get perfumes? (9)
|
| {END (reason) + ER (old queen)} inside (enters) LAVS (loos). I guess the grammar works on this one if “reason old queen” is treated collectively. | ||
| 25 | AMUSING |
Thinking on drop of alcohol can be funny (7)
|
| First letter of (drop of) A[LCOHOL] + MUSING (thinking) | ||
| 27 | COLLECT |
Gather together some protocol lectures (7)
|
| Hidden in (some) [PROTO]COL LECT[URES] | ||
| 28 | ELEVEN |
Sports team possibly drawn by The Spanish (6)
|
| EL (the [in] Spanish) + EVEN (drawn) | ||
| 29 | DRESS TIE |
Earl put on outfit with this on occasion? (5,3)
|
| &lit and DRESS (outfit) + alternate letters of (on occasion) T[H]I[S] + E (earl), with “put on” also indicating the order of the wordplay | ||
| DOWN | ||
| 1 | TUMEFIED |
Swollen stomach I feed without restraint (8)
|
| TUM (stomach) + anagram of (without restraint) {I FEED} | ||
| 2 | BELLY DANCER |
Corporate mover and shaker? (5,6)
|
| Cryptic definition, playing on the informal meaning of “corporation” | ||
| 3 | INCREASED |
When to cut awfully nice red rose (9)
|
| AS (when) inside (to cut) anagram of (awfully) {NICE RED} | ||
| 4 | STING |
Smart son idiot upset heading for graduation (5)
|
| S (son) + NIT (idiot) inverted (upset) + first letter of (heading for) G[RADUATION] | ||
| 6 | TOFFS |
Rotten to run into extremely tedious posh peeps (5)
|
| OFF (rotten) inside (to run into) outside letters of (extremely) T[EDIOU]S, “peeps” here being slang for “people” | ||
| 7 | EGO |
I try to follow edicts… at first (3)
|
| First letter of (at first) E[DICTS] + GO (try), with “to follow” indicating the order of the wordplay | ||
| 8 | SITAR |
One picked up by George Harrison? (5)
|
| &lit and I (one) inside (picked up by) STAR (George Harrison?), an instrument he was famous for studying and popularizing | ||
| 9 | FASTENED |
Imprisoned nurse inside abstained from food (8)
|
| EN (nurse) inside FASTED (abstained from food). Although “fastened” and “imprisoned” can both mean “restrained,” I am not sure they are quite synonyms. | ||
| 14 | BELLIGERENT |
Scrappy green belt I hooked round back of heel (11)
|
| Anagram of (hooked) {GREEN BELT I} around (round) last letter of (back of) [HEE]L | ||
| 16 | GREYLAGS |
Flappers seen with unhealthy-looking convicts (8)
|
| GREY (unhealthy-looking) + LAGS (convicts), referring to a species of goose | ||
| 17 | TRIANGLES |
They have a tinkle in large tins after surgery (9)
|
| Anagram of (after surgery) LARGE TINS, referring to the percussion instrument | ||
| 18 | CASSETTE |
Bag up sofa without using last of adhesive tape (8)
|
| SAC (bag) inverted (up) + SETTE[E] (sofa) minus last letter of (without using last of) [ADHESIV]E | ||
| 21 | CHASE |
Go after husband during legal proceedings (5)
|
| H (husband) inside (during) CASE (legal proceedings) | ||
| 22 | SHINE |
Polish hotel admitted to error with pride ultimately (5)
|
| {H (hotel) inside (admitted to) SIN (error)} + last letter of (ultimately) [PRID]E | ||
| 24 | VICAR |
One collared by police unit mostly on a river (5)
|
| VIC[E] (police unit) minus last letter (mostly) + A + R (river), with “collared” meaning “wearing a collar” | ||
| 26 | USE |
Do drugs you possess deteriorate in the end? (3)
|
| Last letters of (in the end) [YO]U + [POSSES]S + [DETERIORAT]E | ||
I interpreted 23 as you did, Cineraria, and agree with your intro here in that I found this Slormgorm chewier than usual. That made it a very engaging solve.
I liked BELLY DANCER, INCREASED, EGO, CARDS and OTHERS among a slew of amusing surfaces and neat charades.
Thanks Slormgorm and Cineraria.
I needed a bit of time with this one, particularly the NE corner.
All parsed and I thought GENITALS and KNAVES had nice surfaces
I did not know GREYLAGS nor lags for convicts and needed the crossers. One question: is there any reason beyond style that 6 uses peeps rather than people?
Thanks Slormgorm and Cineraria